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Filter guard and air in the canister, any relationship?

parotet

parotet

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Joined
12 Oct 2013
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1,695
Location
Valencia, Spain
Hi all

Two weeks ago I made a DIY inlet guard to keep my baby shrimps in the tank. Curiously I have noticed that since then my canister takes air. Every 2 or 3 days I can here it trying to get rid of it with all kind of burps and strange noises. I thought it could be the co2 micro bubbles swallowed into the canister, but it looks a bit strange as it has been like this for one month or so with no issues. I also thought that it could be some kind of leak in the tubing connections... But Once revised I am pretty sure it is not that.

I googled it and it looks that some folks are having similar issues, specially when the inlet guard gets clogged or the mesh has very small holes. It seems that the canister cannot take as much flow as it delivers and it creates some kind of sucking pressure... I guess that the air come from tubing connections, but not sure.
Any experience?
I prefer having half of my shrimp population living in the canister rather than hearing these noises...

Cheers,
Jordi
 
Its cavitation of the impeller due to insufficient flow. Cavitation - Wikipedia, the free encyclopedia. Not air being sucked in.

Generally bad, will damage the impeller, cause excessive wear of the impeller bearing and more importantly in these type of "motors" cause demagnetisation/failure of the impellor magnet due to it not turning at its normal running speed.

You should not run the impellor in this state.
 
Pumps in general aren't meant to run with restrictions in the inlet, this causes pressure to lower below vapor preasure and tiny bubbles foam.

The best method would be to have the inlet going straight out the bottom of the tank but not many people are willing to cut holes in the bottom of the tank. Try having you're inlet as short as possible with no kinks in it. If you're using an inlet filter make sure that you're using a coarse sponge so it does not block easily, if it does then clean it. Try not stuffing the filter full with filter media, I have course and medium sponge in the bottom trays and then a layer and half of clay rings in the the upper trays. Filter floss tends to clog up very quickly and I've stopped using it. If you are reducing flow with taps on your inlet and outlet just reduce the oulet tap not the inlet tap.

As Ian says cavitation is bad, keep your inlet flow as unstricted as possible.
 
My god... I going to get rid of that inlet guard once I get home! Thanks for quick replies. Definitely it is the filter guard, the glass inlet pipe is a standard one and always worked well. I also keep my canister with only 1 coarse sponge, 2 ceramic ring bags and another coarse sponge. It is quite empty to improve the flow, I would say that only 1/4 to 1/3 of the canister volume is filled (eheim 2215... so quite a lot of free space )
 
Last edited:
parotet said:
My god... I going to get rid of that inlet guard once I get home! Thanks all
Click to expand...
Not a major worry, nothing to wet your pants (or floor !) about. Why do you think filter manufacturers sell spare impellors and bearing shafts ? :)
 
It's more the noise that is annoying, also why not take care of it rather than ramming it and getting replacements.

My DIY pre-filter is a black 10 ppi (coarse) sponge cut and wrapped once around the inlet cage that came with the terta-tec. I then use 2 black zip ties to hold it in place. I don't know how you would do this with a glass inlet pipe. The cage spreads the surface area of the sponge so less likely to clog. If you just put a sponge of the end of the tube the area of flow would quickly clog up.

You could probably let the tank settle for an hour after clean to let the crap settle before turning on the filter.

Edit: Is the glass inlet diameter smaller than the tube that came with the filter? This maybe causing some restriction. Also you could make something like this Got a sponge filter for fry and it trys to float! • Cichlid-Forum put the tube in the glass inlet, make sure the tube has plenty of large diameter holes in it, once again to stop blockage.
 
Hi, tanks for your comments... Regarding the size of the inlet pipes and tubing it is a standard size, thus it shouldn't be this. I have just removed the guard and decided that I will leave the inlet as it was. I had no problem before so I guess I won't have it now.

I am not very worried about the shrimplets. Well, I was, and this is why I put a DIY guard, but I have read lots of threads about people having half of the population in the lower part of the canister...
 
Hi all, it worked. I just got rid of the inlet guard, cleaned the first coarse sponge of the canister... And that's all!
(I found 6 shrimplets of the canister 3 days later, but I think they were ok)

Thanks again
 
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