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13 Jul 2008
Thornhill, Egremont, Cumbria
I've switched from diffusers to DIY CO2 reactor a short while ago and have started suffering from BBA in a couple of areas in the tank.

The way things went, I ended up with a dose of it on the rocks and then it spread to a few plants that had been subjected to the strongest CO2 flow from the previously used diffusers (mainly next to the rocks). Thinking that this will be because of the change of conditions for certain areas of the tank, I have monitored it for a couple of weeks to see where to put a previously removed Koralia back in if needed.

But, the worse affected plants are in the direct flow from the spray bar, the rocks have almost cleared of BBA by themselves and the plants around them appear to be improving too.

CO2 levels are as high as they can go, my WCMMs start to congregate at the top of the tank as the CO2 switches off.

The worst affected plants are Crypt Balansae, although a couple of low growing crypts have been affected too

Tank Details:

180litres, 100cm
CO2 is driven through the reactor, by a 1400lph filter - spray bar runs along back wall pointing at bottom front, supplemented by a 700lph filter.
Lighting: 3 x 39W - 8 hours (2 @ 10000K, 1 @ 6500K)
CO2 on 2.5 hrs before lights, off 2 hours before lights

Main question is how come the worst affected plants are those in direct contact with the CO2 outflow, is there anything else that could be affecting them (coincidence that it's the crypts that are worse affected ?)

As I have only changed it a couple of weeks ago - do I just need a bit more patience to see how things continue to progress with the new CO2 flow around the tank.

Incidentally, the drop checker has been placed at the points in the tank which are the hardest areas for flow to get to and ends up yellow side of green, whilst lime green for lights on.

Thanks, Al


Expert/Global Moderator
11 Jul 2007
Chicago, USA
Hi Al,
Pummeling the plants with flow can sometimes be counterproductive. The spraybar normally generates better flow patterns if the spray is directed horizontally instead of pointing down. You can add easycarbo or excel to knock back the BBA.


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