My comments are based on much less experience than Karen's, but I'll offer them anyway and perhaps you may find some use in the them. I've heard to views strongly stated re BGA and experienced both. One that it's a matter of too little phosphate and the other too little nitrate. Too little of of either will mean a relative excess of the other -- if there isn't enough of one, plants can't use up the other and then the other tends to build up. Which leads me to what Karen has already expressed, that it's a question of nutrient balance. If you can check your phosphate or nitrate levels, or both, you'll probably find one or the other is in excess or (I'll wager more likely) that the other is rather low. Boost the low one and the BGA is likely to subside. We've heard for so many years that nitrates and phosphates cause algae. Really, a lack of flourishing plants causes algae. And plants need nitrate and phosphate to flourish. When they are not in balance, one algae or another (or BGA) seems to find that condition just right for flourishing. Fast eradication means cleaning up what BGA you can -- wiping, clipping, pruning the visible material, a large water change to reduce any excess nutrients -- but nutrient balance is essential in my small experience to *keeping* BGA at bay and something probably needs to be added when BGA shows up. Luckily, BGA wipes up rather easily from most surfaces. I find good results maintaining a ratio of 20:10:1 of potassium, nitrate, and phosphate. And the amount of potassium seems to matter least so long as there is a reasonable amount present -- so I'm never very cautious about dosing dipotassium sulfate (K2SO4). In a slow grow, low light tank, I'll aim for about 5 ppm nitrate and 0.5 phosphate. In a tank with with more than 2 watts per gallon, I'll aim for 10 ppm nitrate and 1.0 ppm phosphate. The precise level is not so important as the keeping the rations moderately close. I personally suspect that currents, or lack of them are less responsible for BGA than nutrient balance. When I get BGA, it's as often in the strong current areas and any other. I'm only saying chaeck that nutrient balance fist before you think about change your waterflows. Scott H. --- Karen Randall <krandall@rdrcpa.biz> wrote: > Hi Randy, > > I've cc'd the AGA member list so that others can add > their $.02. Cyanobacteria is almost always a problem of > nutrient imbalance. You didn't say waht your PO4 level > was, but that would be the first place I looked. The > other thing that can cause a problem is areas where water > movement is not good. (which can cause excess nutrients > to build up in pockets in the tank) a power head or two > can alleviate that problem. > ----- Original Message ----- > From: Randy Pullen > To: krandall@rdrcpa.biz > Sent: Thursday, August 12, 2004 11:20 AM > Subject: BGA Help > > > Karen, > Since you offered, I would like to ask how I may get > rid of Blue Green Algae laying in sheets on substrate and > plant leaves. > PH 6.8 KH 4 adding CO2 16 - 20ppm NO3= 5 - 10 Have been > adding PMDD, 2.8 watts per gallon 10hrs. > 50% water changes weekly. > Your help is appreciated. > Best Regards, > Randy > _______________________________________________ > AGA-Member mailing list > AGA-Member@thekrib.com > http://lists.thekrib.com/mailman/listinfo/aga-member > ===== Want to get dirty but stay clean? Diana Walstad, author of _Ecology of the Planted Aquarium_ will discuss soil supplemented aquarium substrates at the 2004 AGA Convention. Convention Details/Registration at aquatic-gardeners.org & gwapa.org _______________________________________________ AGA-Member mailing list AGA-Member@thekrib.com http://lists.thekrib.com/mailman/listinfo/aga-member