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Oase BioMaster Thermo External Filter

The white dot is the 2mm hole which you can't see side way, in the other picture. So the hole is vertical, parallel with the sponges pipe.
 

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Aquascape20, one question please: so you don't use any sponges in the prefilter? But you still have the central pipe?
So as I said, the gas is collected in the prefilter. If you don't use the sponges then will be much easier for it to pass through and not to collect. The 2 mm bypass hole will fix the issue irrespective if you have or not the sponges in the prefilter or if you have one or two inlet pipes.
If i remove central pipe. All media goes out of center in bucket.
 
Can you explain why two inlet pipes somehow address the problem?

Canister filters can accumulate air if there is back pressure in the system or the pump is overloaded. In the BioMaster this can be addressed by (1) replacing the pre-filter pipe with a pipe with a wider diameter (~21mm) and more holes, (2) not restricting the output flow, i.e. keeping the pressure-side slider fully open, and (3) not overloading the filter with media. These will increase the flow, reduce the load on the pump, and will minimize air accumulation. I have two BioMaster filters and air only accumulates if I constrain the flow. Otherwise, I have zero air accumulation issues. Removing the pre-filter sponges is not a good option IMO - better to use a different filter then.
When i unlock the prefilter it comes water. So I decided, in the filter pressure goes up. Then I remember the ehim 2080 which it has two inlet. So I tried it. and worked. but not fix fully. Like you said it is not a good option removing prefilter sponges. Most of the people buy this because of prefilter feature.
 
If i remove central pipe. All media goes out of center in bucket.
What media? I was thinking you have the prefilter empty.
When i unlock the prefilter it comes water. So I decided, in the filter pressure goes up. Then I remember the ehim 2080 which it has two inlet. So I tried it. and worked. but not fix fully. Like you said it is not a good option removing prefilter sponges. Most of the people buy this because of prefilter feature.
When you open the prefilter, your pump is stopped and you have the water column pressure (prefilter up to surface level of the tank).
When the pump is working then it's create a pressure change which is negative before pump and positive behind.
So in order to work you need to create suction on the inlet pipe (pipes in your case). When you stop the filter, the pressure difference disappears and the water stops flowing through and you have only the static pressure of the water.
 
What media? I was thinking you have the prefilter empty.
When you open the prefilter, your pump is stopped and you have the water column pressure (prefilter up to surface level of the tank).
When the pump is working then it's create a pressure change which is negative before pump and positive behind.
So in order to work you need to create suction on the inlet pipe (pipes in your case). When you stop the filter, the pressure difference disappears and the water stops flowing through and you have only the static pressure of the water.
Prefilter empty, i mean filter media in the other buckets.

But my other external filter does not have pressure difference. When I closed the valve then open the filter head does not overflow water on filter head. But oase do.
 
Prefilter empty, i mean filter media in the other buckets.

But my other external filter does not have pressure difference. When I closed the valve then open the filter head does not overflow water on filter head. But oase do.
Don't worry about the media in the trays is not going anywhere. If you remove the pipe in the prefilter, you will see even more improvement in the flow and gas burping.
Regarding the water spillage, when you open the prefilter, that is produced by the fact that water can go up into the priming button (the blue pushing button) which in turn will compress the air above it in the button. When you remove the prefilter a small quantity of water it's leaking out pushed by the expanding air. Unfortunately you can't change anything about that issue.
 
Hi all

Created an account after reading through the thread from first post, and that it seems that no one has mentioned it before. Hoping that someone would find this helpful when they face the same problem I did.

This refers to the leaking of the filter that seems to be coming from the latches of the main body and/or the main gasket between the filter head and the filter body, as shown below (video here). Changing the gasket did not help, lubricating the o-rings and silicon gaskets did not help, emptying the media baskets did not help.

I have done the following to no avail:
1. Re-install the main gasket on the filter head to ensure that there is no debris;
2. Cleaned the insides of the filter head and pre-filter to ensure that there is no debris;
3. Carefully ensured that there is no warpage of the filter media baskets;
4. Ensured that the filter head is seated properly before locking the four latches;
5. Ensured that all hose fittings are secured properly (the leaks do not come from the hose fittings);
6. Ensure that there is no damage to the main filter gasket (and bought a new one to test, since most leaks are caused by gasket problems);
7. Cleaned the O-ring situated near the hose intake part of the filter head;
8. Ensured that the propeller is sitting properly inside the chamber, with the plastic cover secured in place;
9. Ensured that the slot for the heater is covered properly, with its o-ring installed;
10. Checked that none of the components are damaged/cracked; and
10. Ensured that both the blue latches of pre-filters and hose adapter are locked securely (pre-filter latch first, then hose adapter).

After several troubleshooting (and days of frustration) and almost giving away the filter for scraps, I found that the culprit was actually the hose adapter seen below:


Not entirely sure what happened to the old hose adapter of mine (it is superficially flawless), but this resolved the issue immediately. Maybe there is a very small hairline crack somewhere within that I missed.

Bottom line is, if the filter is leaking, check whether your main filter gasket is fine AND whether your hose adapter is working fine too.
 
Does anyone know if all biomaster heads are compatible with each other? I’m thinking about buying a 250 head and fitting it onto my 600. The widths are all the same.
 
Does anyone know if all biomaster heads are compatible with each other? I’m thinking about buying a 250 head and fitting it onto my 600. The widths are all the same.

Yeah, I think they are. Certainly the 850 and 600 heads are interchangeable.
 
The white dot is the 2mm hole which you can't see side way, in the other picture. So the hole is vertical, parallel with the sponges pipe.
I have tried everything except for removing the prefilter (which I dont want to) but nothing has worked and the filter has been spewing bubbles past a couple of years. So I tried this last night and surprisingly I have not seen the bubble issue as of this morning yet. I will keep you guys updated.
 
I have tried everything except for removing the prefilter (which I dont want to) but nothing has worked and the filter has been spewing bubbles past a couple of years. So I tried this last night and surprisingly I have not seen the bubble issue as of this morning yet. I will keep you guys updated.
Update: The filter is still blowing air bubbles. Maybe the hole should be bigger? Mine is only like 1.5mm.
 
Never got round to posting but near the end of last year my 600 thermo leaked and drained 75% of the contents of my 180L tank on the floor. I got the updated top housing some months before that but I never did find the root cause of the leak. It seemed like there was almost too much pressure inside the filter and it was forcing water past the seals, even though the filter was not heavily stocked and media was clean and free flowing. After a run of nothing but issues, including previous leaks (caught early), with these filters I threw it out and will never use Oase products again!
 
Hi all

Created an account after reading through the thread from first post, and that it seems that no one has mentioned it before. Hoping that someone would find this helpful when they face the same problem I did.

This refers to the leaking of the filter that seems to be coming from the latches of the main body and/or the main gasket between the filter head and the filter body, as shown below (video here). Changing the gasket did not help, lubricating the o-rings and silicon gaskets did not help, emptying the media baskets did not help.

I have done the following to no avail:
1. Re-install the main gasket on the filter head to ensure that there is no debris;
2. Cleaned the insides of the filter head and pre-filter to ensure that there is no debris;
3. Carefully ensured that there is no warpage of the filter media baskets;
4. Ensured that the filter head is seated properly before locking the four latches;
5. Ensured that all hose fittings are secured properly (the leaks do not come from the hose fittings);
6. Ensure that there is no damage to the main filter gasket (and bought a new one to test, since most leaks are caused by gasket problems);
7. Cleaned the O-ring situated near the hose intake part of the filter head;
8. Ensured that the propeller is sitting properly inside the chamber, with the plastic cover secured in place;
9. Ensured that the slot for the heater is covered properly, with its o-ring installed;
10. Checked that none of the components are damaged/cracked; and
10. Ensured that both the blue latches of pre-filters and hose adapter are locked securely (pre-filter latch first, then hose adapter).

After several troubleshooting (and days of frustration) and almost giving away the filter for scraps, I found that the culprit was actually the hose adapter seen below:


Not entirely sure what happened to the old hose adapter of mine (it is superficially flawless), but this resolved the issue immediately. Maybe there is a very small hairline crack somewhere within that I missed.

Bottom line is, if the filter is leaking, check whether your main filter gasket is fine AND whether your hose adapter is working fine too.

Hi, this exact puzzling leak happened to me too!! And I tried in vain to look for ways to resolve it.
The first time it happened, my Oase just started leaking water drops from one side only (I only noticed it when the floor around the filter got soaked). I stopped the filter and did practically everything you did! I was so frustrated I let my tank stay unfiltered for two days while trying to research the issue. Of course, that fouled out the water in the tank and I had to clean it. When I restarted, the leak just vanished, miraculously!
Then my schedule to maintain the tank came after three weeks and when I restarted the filter, the leak just returned, and it was worse. There were leaks from two sides and the leaks were stronger than before.
1. The primary assumption I had was that the gasket was not sitting properly, so I reseated it and it did not solve the issue.
2. I read of a guy putting vaseline in the gasket (I am aware that petroleum grease can damage some types of gasket) so I tried it too
3. I wrapped the gasket with a double wounding of PTFE and tried
4. I dismantled the filter pump head (loosened and remove four screws) and cleaned the cavity
5. I opened the cavity where the motor was seated (secured by another set of four screws) and cleaned away
Nothing helped.
All this time while I am doing all these modifications, the inlet-outlet hose connector piece is attached to both the inlet hose and outlet hose, that are in turn connected to the inlet pipe and the lily pipe respectively and is hanging conveniently from the tank, ready to be refitted back, once I the permutation I am trying on is ready. ....Big Mistake!
Oase has made it so convenient to just detach the inlet-outlet piece without decoupling the lily pipe/ inlet pipe, hoses and all. Then to just plug the set up into to the top of the filterhead and then to swing the lock in.
In most cases, this inlet-outlet connector-adaptor piece will be hanging just under the cabinet. Given how the two hoses (inlet and outlet) would most likely twist the connector-adaptor piece while one tries to awkwardly refit it into the filterhead in the limited space under the cabinet, the chance of getting this part imperfectly plugged and locked into place is very high.
I observed that it is possible to seat the hose connector-adaptor in several different angles and slide the lock close but still get water leaking and filling the filterhead cavity. Leaks will begin weeping into the sides almost at once.
How I solved it? I just made sure the hose-connector-adaptor is firmly and securely seated on the filterhead before swinging the lock. No leaks, at least in my case.
 
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Hi all

Created an account after reading through the thread from first post, and that it seems that no one has mentioned it before. Hoping that someone would find this helpful when they face the same problem I did.

This refers to the leaking of the filter that seems to be coming from the latches of the main body and/or the main gasket between the filter head and the filter body, as shown below (video here). Changing the gasket did not help, lubricating the o-rings and silicon gaskets did not help, emptying the media baskets did not help.

I have done the following to no avail:
1. Re-install the main gasket on the filter head to ensure that there is no debris;
2. Cleaned the insides of the filter head and pre-filter to ensure that there is no debris;
3. Carefully ensured that there is no warpage of the filter media baskets;
4. Ensured that the filter head is seated properly before locking the four latches;
5. Ensured that all hose fittings are secured properly (the leaks do not come from the hose fittings);
6. Ensure that there is no damage to the main filter gasket (and bought a new one to test, since most leaks are caused by gasket problems);
7. Cleaned the O-ring situated near the hose intake part of the filter head;
8. Ensured that the propeller is sitting properly inside the chamber, with the plastic cover secured in place;
9. Ensured that the slot for the heater is covered properly, with its o-ring installed;
10. Checked that none of the components are damaged/cracked; and
10. Ensured that both the blue latches of pre-filters and hose adapter are locked securely (pre-filter latch first, then hose adapter).

After several troubleshooting (and days of frustration) and almost giving away the filter for scraps, I found that the culprit was actually the hose adapter seen below:


Not entirely sure what happened to the old hose adapter of mine (it is superficially flawless), but this resolved the issue immediately. Maybe there is a very small hairline crack somewhere within that I missed.

Bottom line is, if the filter is leaking, check whether your main filter gasket is fine AND whether your hose adapter is working fine too.

Yep, this happened to me as well!

I had an Oase 250, which would not seal. Between straight-away and 15 minutes, water would start coming out the sides, and bubbles and gurgling also preceded this. Water being water becomes painful when trying to work out where the leak is coming from. Ultimately, I had an idea (by process of elimination and research) and replaced the inlet/outlet that plugs into the head unit. As soon as that was replaced, there was no air, gurgles, or leaks. It's been running fine ever since and that's been around 6 months.

I noticed some complaints about the flow of the Oase not reaching the max as defined in the specifications. The 250 is meant to be 1100L/ph, but mine never reaches that - which makes sense when you take into the head height. Mine is about 0.90M, and it flows at around 550L/ph - which is almost spot on the Oase performance curve. On my 100L tank, that is enough, and I now have two Oase 250's for redundancy purposes anyway. (I also used to run an inline UV, which did take the flow down even more, so anything extra will take more away from the flow rate. I don't run that anymore with two Oase 250's running).

For the time being, I am committed to Oase (for good and bad), and after the problems went away, I have been very happy with what it delivers.
 
I’ve had quite a few external canister filters and I don’t think you can beat the original Eheim concept that’s still available as the Eheim Classic series and the ADA Superjet. All the others that I’ve seen can leak water in unseen places in and around the head. The classics have three seals and it should be fairly obvious which one is leaking. There is an O ring on the inlet bend at the bottom of the filter. The large main O ring that seals the head/ canister, and a small O ring inside the head unit. The latter seal is accessible by removing the head cover. The ADA only has the large head seal but it can also obviously leak on the short length of pump hose.

Apart from the difficulty in locating leaks on more modern filters another issue for me is one of bypass. This is where water does not fully flow through the filter in a manner that owners may expect. I even found this with my Eheim Classic 250 until I removed the supplied basket. I think in some filters a certain amount of bypass is deliberately designed into the filter in order to maintain a high flow level. It’s either that or the designers have done a poor job? Does bypass matter though as long as the majority of the water is properly filtered through all the media? Probably not.

The problem is that many buyers seem to struggle with setting up a filter unless it has features like built in priming and quick release manifold etc.

My main issue is one of noise. Modern external canister filters should by now be virtually silent but most of them aren’t.

I’m running a Biomaster 350 and it’s fairly quiet, but only after jamming a small piece of plastic near the top of the impeller housing. And yes, it is one of the later models that supposedly fixed the noise issue. It was quiet to start with but developed the perhaps inevitable humming noise after a couple of months use. It also suffers pretty bad bypass and the pre filter doesn’t work anywhere near as well as I thought it might.

I’m also currently running a Classic 250 which is sadly much nosier than the original German manufactured one I had in the 1980’s. At least it doesn’t suffer bypass though since I removed the basket.

You may expect that something as solid and simple looking at the ADA superjet (and clones) would be the perfect solution, but aside from the premium price I’ve also read that some have been quite noisy?!
 
I’m running a Biomaster 350 and it’s fairly quiet, but only after jamming a small piece of plastic near the top of the impeller housing. And yes, it is one of the later models that supposedly fixed the noise issue. It was quiet to start with but developed the perhaps inevitable humming noise after a couple of months use. It also suffers pretty bad bypass and the pre filter doesn’t work anywhere near as well as I thought it might.

I’m also currently running a Classic 250 which is sadly much nosier than the original German manufactured one I had in the 1980’s. At least it doesn’t suffer bypass though since I removed the basket.
It's funny, as for all the little problems and issues with my Oase Biomaster journey, noise has never been one! Both run very quietly for me and (if the tank was in the bedroom) could easily sleep in the same room near the tank without any issue with both running.

Apart from the difficulty in locating leaks on more modern filters another issue for me is one of bypass. This is where water does not fully flow through the filter in a manner that owners may expect.
I am always cautious of leaks in canisters. There is a real risk. I have tried to mitigate this by having a real-time wireless heater alarm with temperature probes near the top of the tank. Not only is it sensitive to temperature change, but it also acts as a rudimentary alarm for water not covering the probes via % change or actual temp change. Being wireless it gives me an alarm wherever I am. The inflows are set up so that the tank will not completely drain all water, offering me the chance to save some fish - although saving my marriage could be tough with all that water on the floor.

I am interested in how you worked out the flow was being bypassed. I cannot see into my filters, so this is interesting to me.
 
I’ve had quite a few external canister filters and I don’t think you can beat the original Eheim concept that’s still available as the Eheim Classic series and the ADA Superjet. All the others that I’ve seen can leak water in unseen places in and around the head. The classics have three seals and it should be fairly obvious which one is leaking. There is an O ring on the inlet bend at the bottom of the filter. The large main O ring that seals the head/ canister, and a small O ring inside the head unit. The latter seal is accessible by removing the head cover. The ADA only has the large head seal but it can also obviously leak on the short length of pump hose.

Apart from the difficulty in locating leaks on more modern filters another issue for me is one of bypass. This is where water does not fully flow through the filter in a manner that owners may expect. I even found this with my Eheim Classic 250 until I removed the supplied basket. I think in some filters a certain amount of bypass is deliberately designed into the filter in order to maintain a high flow level. It’s either that or the designers have done a poor job? Does bypass matter though as long as the majority of the water is properly filtered through all the media? Probably not.

The problem is that many buyers seem to struggle with setting up a filter unless it has features like built in priming and quick release manifold etc.

My main issue is one of noise. Modern external canister filters should by now be virtually silent but most of them aren’t.

I’m running a Biomaster 350 and it’s fairly quiet, but only after jamming a small piece of plastic near the top of the impeller housing. And yes, it is one of the later models that supposedly fixed the noise issue. It was quiet to start with but developed the perhaps inevitable humming noise after a couple of months use. It also suffers pretty bad bypass and the pre filter doesn’t work anywhere near as well as I thought it might.

I’m also currently running a Classic 250 which is sadly much nosier than the original German manufactured one I had in the 1980’s. At least it doesn’t suffer bypass though since I removed the basket.

You may expect that something as solid and simple looking at the ADA superjet (and clones) would be the perfect solution, but aside from the premium price I’ve also read that some have been quite noisy?!

I use superjets an the only noise is from vibration on the stand. Easy fix is a rubber pad under them.
 
I am interested in how you worked out the flow was being bypassed. I cannot see into my filters, so this is interesting to me.
The bio media in one of the top trays gets very dirty. Exactly the same media in the Eheim stays relatively clean. When you have a basket system it’s obvious that water can travel outside as well as through the baskets. With something like the Eheim or Superjet this obviously can’t happen, except perhaps if you choose to use bagged media?

I’ve also found that to some extent quick release manifolds are not only a liability - as a potential source of leaks, but also a bit pointless if you use double taps on the hoses as I do, even on the Biomaster. Without double taps periodic hose cleaning is not so easy. Having said that the Biomaster manifold is pretty good and seems to work well. I have, of course bought a spare seal as leakage on this is surely only a matter of time?
 
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