Low light BBA

[zenkatydid]

I have the beginnings of BBA in my low light tank. It has about 1wpg, and I dose K (due to mild K deficiency signs on the hygro), P (to avoid GSA - all my tanks get it, possibly not necessary here) and trace twice a week, on different days. I don't dose C in any way. I do a water change every week of about 20% because it is stocked quite heavily - it is a guppy breeder (and cory) tank, and you know how they are. I know Tom Barr will probably say don't do any water changes, but due to the heavy stocking, I fear the NO3 will go through the roof if I don't. What should I do?

 

[zenkatydid]

*taps the microphone* hello?

 

[rich311k]

BBA comes from fluctuating COP2 levels. The water changes are causing the fluctuations. Do you have an airstone running or something chopping up the surface to keep the CO2 levels at ambient levels?

 

[zenkatydid]

no i don't, but i could add one easily - would i still be able to do weekly water changes if i had an airstone?

 

[Plantbrain]

Try adding more plants, floating water sprite will mop up the nutrients.
You can also add denitrifying media in the filter etc.

I've not found issues with higher loads and NO3 build up.
But I tend to pack as many plants as will fit and make sure the stocking is reasonable.

There's going to be a trade off here you are not going to get around without going CO2 or Excel etc.

Regards,
Tom Barr

 

[Lonewolfblue]

no i don't, but i could add one easily - would i still be able to do weekly water changes if i had an airstone?

I would continue water changes. As stated above, bba is induced by fluctuating CO2 levels. The CO2 get's increased when you do the water change, then decreases due to the plants using it up. The airstone will keep these levels up as the plants are using it.

Also, if you don't want to add an airstone, then a small powerhead would work as well, on the back wall of the tank, at the waterline, pointed slightly up so you get a good ripple going on the surface. And with the gas exchange taking place, the powerhead will circulate it down into the tank.

 

[Jchillin]

Interesting. My experience is a bit different than what the other members mentioned. I ran my low-light tank with an airstone for about a year and a half and didn't have an issue with BBA. I also did PWC's every two weeks.

I then overstuffed the tank with plants, including some hungry root feeders (amazon swords) and suddenly, BBA surfaced. I also have a pretty decent fish load (see my profile) but nevertheless, it was there. I had no choice but to start dosing Excel and KNO3. The KNO3 was desperately needed because although the bioload was decent, I was bottoming out on KNO3.

This combo has worked pretty good so far. Yes, I still run the airstone.

 

[jsoong]

My experience is similar to Jchillin's. I am still battling BBA, more or less to a draw. As soon as the NO3 level bottoms out, the BBA starts to take over, once I up the NO3, green algae begins to over run the BBA. My current strategy is to keep the NO3 up, let the green algae kill off the BBA, then deal with the green ones later .... I am not sure why my plants are not out-competing the BBA , maybe I need more.

 

[rich311k]

I think if you run an airstone, then your CO2 levels will at least stay at a constant 3ppm. Some Excel will help kill the stuff. You can always remove any leaves that are too far gone.

 

[Purrbox]

A way around the issue of the fluctuating CO2 levels due to water changes is to use aged water. Let the water you're going to use either sit for 24hrs or aerate it for at least an hour. This should remove the extra CO2 so that you won't get a spike in CO2 from the water change.

 

[Plantbrain]

I ran my low-light tank with an airstone for about a year and a half and didn't have an issue with BBA. I also did PWC's every two weeks.

I then overstuffed the tank with plants, including some hungry root feeders (amazon swords) and suddenly, BBA surfaced. I also have a pretty decent fish load (see my profile) but nevertheless, it was there. I had no choice but to start dosing Excel and KNO3. The KNO3 was desperately needed because although the bioload was decent, I was bottoming out on KNO3.

This combo has worked pretty good so far. Yes, I still run the airstone.

But..........you did not have a sdtuffed tanks prior, then you added a lot of plants, thus the CO2 uptake went up..............prior, it was stable and balanced.

If you reduced the bioload, you likely would not have had the issues and it could have been due tio low nutrients, that slowed CO2 uptake, PO4 limitation etc.

You did not test it seems(at least it's not reported), so it's hard to say what the nutrients where doing before and after, but you know the demand for CO2 increased a great deal........

Regards,
Tom Barr

 

[zenkatydid]

thanks for all the input guys. this is supposed to be my non-thinky tank - i already have a complicated fighting everything tank, so i want to keep this as simple as possible. for now, i will put an airstone in and see what effect that has. i really don't want to go the excel/ferts route on this tank, but we will see.

tom, in your original advice you say try adding more plants to soak up nutrients - but according to jchillin's experience, adding more plants suddenly increases co2 uptake and thus causes bba. is that right? how is his situation different to mine?