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Can you have too much flow?

sbishop1488

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22 Jan 2021
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Hartlepool
Hi, I have an ADA 60-P with a Oase BioMaster 250 Thermo running CO2 (with glass lily pipes) and out of the box the max flow of the filter is 900 lph which is 15 times turnover. Now I have heard people using the 350 on a tank this size which seems crazy because it’s very turbulent at the opposite end of the tank even with the 250. I think having this high flow causes issues with algae (BBA specifically). I’m guessing this is to do with the higher O2 levels where the flow is fastest causing CO2 fluctuations. So is it possible to have too much flow? Who’s had problems arise from high flow and what issues have you had?

Thanks
 
Hi all,
I think having this high flow causes issues with algae (BBA specifically).
I've noticed (mainly on <"PlanetCatfish">) that a lot of the really high flow tanks have BBA, they don't tend to be planted and the tanks really have "white water" with a huge amount of flow and bubbles.

file.jpg


I mainly get it on outflow from the filter and <"exposed sponges">, possibly because those are areas that don't benefit from Ramshorn snail grazing.

cheers Darrel
 
The only reason Id reduce flow is if the fish were struggling or pinned to the glass. Other than that...the more flow/distribution the better.
Make sure your CO2 is high enough and that it reaches approx 30ppm before the lights go on. Best to manually remove as much BBA as you can.
I agree with Darrel regarding non planted tanks and BBA. When I used to work in an LFS, most of the customers with BBA had non planted tanks with messy fish and large airstones/air pumps. Too much to be a coincidence.
 
Hi all,

I've noticed (mainly on <"PlanetCatfish">) that a lot of the really high flow tanks have BBA, they don't tend to be planted and the tanks really have "white water" with a huge amount of flow and bubbles.

file.jpg


I mainly get it on outflow from the filter and <"exposed sponges">, possibly because those are areas that don't benefit from Ramshorn snail grazing.

cheers Darrel
Thanks, that’s the really strange thing, there is zero (visible anyway) BBA on any hardscape (I have a mix of manzanita wood and Frodo stone) it’s only on my carpet and leaves on the plants. So frustrating because the tank looks great from a distance but awful when up close. Originally I had the inlet/outlet at the back right hand corner of the tank and noticed the BBA on my Java Fern, close to the outlet and then it spread in line with the flow. I moved the inlet/outlet to the front right and now I see it on the carpet at the front.
 

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The only reason Id reduce flow is if the fish were struggling or pinned to the glass. Other than that...the more flow/distribution the better.
Make sure your CO2 is high enough and that it reaches approx 30ppm before the lights go on. Best to manually remove as much BBA as you can.
I agree with Darrel regarding non planted tanks and BBA. When I used to work in an LFS, most of the customers with BBA had non planted tanks with messy fish and large airstones/air pumps. Too much to be a coincidence.
Cheers, my fish tend not to go down that end of the tank, which is why I’m wondering if the flow is too high. I’ve heard a good flow to achieve is 10x turnover but 15x seems a bit much for the fish and wondered if this also could be the problem with my BBA since I have a CO2 Art in-line diffuser and wandered if the flow was to turbulent which would have a high O2 an lower / fluctuating level of CO2. I’m on the verge of giving up on the tank and stripping it, disinfecting everything and rebuilding, just don’t want the same thing to happen again. The problem only seemed to appear after I added the CO2 system the tank was lovely before that, I only added the CO2 since I wanted optimum plant health rather than being bothered about speedy growth etc.
 
Your frustration is perfectly natural.
If you didnt have BBA before, but you do now, it sounds like the BBA is a result of fluctuating levels of CO2. The plants struggle to adapt to the changing levels.
If you dont have one already, try get hold of a drop checker, 4dkh solution and bromo blue reagent. Lime green colouration is a good colour to aim for....just keep an eye on the fish. You'll want the drop checker to show lime green before the lights come on so set the CO2 to come on 1 or 2 hours before the lights. Turn it off 1 hour before the lights go off. I'd also only have the lights on for 8 hours a day. Keep this up with weekly water changes and manual removal of algae and you should start to see an improvement.
 
Hi all,
I’m guessing this is to do with the higher O2 levels where the flow is fastest causing CO2 fluctuations.
That is an interesting question. In the <"PlanetCatfish"> link Eric Thomas (@bekateen) has bred <"Dekeyseria picta (L052)"> a highly rheophilic plec that needs soft, warm, very well oxygenated water.

To get that degree of oxygenation you need a very large gas exchange surface, so levels of CO2 should also <"track atmospheric levels">, and be fairly constant as well. When you add CO2 you are going to get more out-gassing in turbulent water, for the same reasons.

I'm not a CO2 user, but I don't get BBA on the plant leaves, my guess is that the Ramshorn snails in my tanks <"graze it off with the biofilm">.

cheers Darrel
 
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Your frustration is perfectly natural.
If you didnt have BBA before, but you do now, it sounds like the BBA is a result of fluctuating levels of CO2. The plants struggle to adapt to the changing levels.
If you dont have one already, try get hold of a drop checker, 4dkh solution and bromo blue reagent. Lime green colouration is a good colour to aim for....just keep an eye on the fish. You'll want the drop checker to show lime green before the lights come on so set the CO2 to come on 1 or 2 hours before the lights. Turn it off 1 hour before the lights go off. I'd also only have the lights on for 8 hours a day. Keep this up with weekly water changes and manual removal of algae and you should start to see an improvement.
I have a drop checker as shown in the attached pic. I was originally running my Twinstar 600E at 40% for 6 hrs a day but ramping up the intensity slowly to 60% and my light duration to 8 hours after I’ve done this, getting a lot more pearling now, but the BBA is still quicker than the growth, using EI ferts, so cutting back each week is becoming depressing.
 

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I had the most bba before I kept plants. I kept dirty cichlid and bba covered rock, gravel and filter outlets. I don't think high flow is the cause of bba, but rather bba, if present, prefers surfaces with good circulation. If there is not enough light to grow bba, high flow will not trigger bba. But bba light requirement is the lowest among other algae. If there is enough light to grow java fern, there is enough light for bba to thrive.

After I learned how to keep plants, I no longer have bba as it is the easiest algae to get rid of. bba responds to H2O2 and Glutaldehyde treatment better than other algae, and healthy plants resist bba attachment.
 
 
In one of my older scapes, I have had BBA grow on the outlet (plastic) pipe and not in the rest of the tank. Oh...and the BBA grew on the airstone (I have air in my tanks 4 hrs after co2 is off (2hrs after lights are off). However, the rest of the plants and hardscape has absolutely no BBA.

I also have an ADA 60P with the oase biomaster thermo 250 with Lilly pipes (picture attached). I have too wondered about swapping my Oase 250 onto a 45P (yet to be scaped) and upgrading to a 350 on the ADA60P. I have a YouTube channel which shows setting up the substrate and hardscape, then planting, it all going wrong in the beginning and recently a ~3 month update where the scape looks great. Just had a look at my ADA60P now and the only BBA I can see is some very minor spots on SOME of the cyperus helferi and some helanthuim tenelum green. Tank needs a trim/thinning (not done since I scaped the tank).

When injecting CO2, too much flow can cause excess diffusion of co2 on the surface. Conversely, not enough flow will give "dead spots" with areas of poor circulation and low CO2 levels and will give algae issues if exposed to light and excess nutrients. Therefore it is a balance between having too much and not enough flow. You could put your co2 drop checker in an area where you think there will be less flow and measure the co2. I am using lean fert method (ADA ferts). At some point I will nip into my lab and get dry salts although one has be extremely careful to ensure the exact specifications of lab based chemicals. Some chemicals are reagent grade, some are analytical grade and contain different amounts of copper and sulfur in addition to other trace elements.

Below: how the scape looks today - the green moss in the bottom left corner are some matts of fissidens fontanus that I am growing out for future scapes, that moss is not part of the scape haha.

Hope this helps.
20210202_105443.jpg
 
In one of my older scapes, I have had BBA grow on the outlet (plastic) pipe and not in the rest of the tank. Oh...and the BBA grew on the airstone (I have air in my tanks 4 hrs after co2 is off (2hrs after lights are off). However, the rest of the plants and hardscape has absolutely no BBA.
View attachment 161973
You can have bba on filter plastic and hard surfaces even though healthy plants are resistant to bba attachment. I spray H2O2 on all exposed hard surfaces during water change, and dose 2 ppm Glutaldehyde (initial Excel dosage) after water change to take care of all submerged surfaces. I haven’t had my trace of bba anywhere since I undertook the routine measure, and I don’t know if it makes a difference if I sop doing it as my setup is fully balanced.
 
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