johnny70 said:
its that easy? wow
Well, yes and no. You do have to remove the GSA that's there. It's important to remember that PO4 is not merely some kind of antidote to GSA. In fact GSA consumes PO4 as well as other nutrients. GSA spores are all over the tank and are actually camped out on the leaf surface waiting, like vultures for an opportunity to pounce. What the spores (which we cannot see and which are innocuous ) are waiting for is a signal in the water column that it is a good time to bloom. The signal occurs when the leaves begin to starve. Starvation causes the leaf structure to begin decaying at which time ammonia and other organic products get ejected into the water column. The spore process the signals and determine that it's the right time to bloom. Since they are sitting right on top of the leaf they can then feed on the "bleeding" plant. That bleeding includes NH4 as well as PO4 and other products by the way.
By adding more PO4 what we are doing is satisfying the plants demand for PO4 so that it does NOT bleed and therefore does not release weakness signals into the water column for the algae spores to read. Having satisfied the plants requirement for PO4 by upping the dosage there is not much we can do about the GSA that has already bloomed because the bloomed algae then feeds off whatever we are dosing. This duality is what makes algae such a tough customer. The only thing you can do is to physically remove as much of the damaged leaves we can, clean the glass or other affected surfaces, do more frequent water changes (dosing after each change) and to perhaps treat with Excel/Easycarbo to kill what remains.
So the PO4 keeps the plants healthy and stops more spores from blooming but it does not stop the GSA that has already bloomed. I reckon it's important to understand this. If you were merely seeing a bit of GSA on the glass it would be easy to simply wipe the glass and up the dosage. If you are seeing it on the plant surfaces then this means starvation has begun so that more stringent measures as discussed above are required.
Hope this clarifies.
Cheers,
