We recently had to remove all of the fish and plants from our tank (for about 4 days) while we replaced the top frame. When we moved the fish back into the tank we used the water from the fishes temporary tank (the plants were in another tank).
About a week after putting the plants and fish back in the tank we started with this problem:
A slimy algae is all over the tank and seems to doubling in size each time we look.
120 gallons - 5' long (2 built-in overflows on back sides)
4 T5 power compacts - 54 watts each
2 halides - 250 watts each
power compacts - 12 hours
halides - 10 hours
CO2 injection controlled by PH - 6.9
constant dripping water changes - soft, acidic well water
substrate - EcoComplete (we added 20 lbs the day before we replaced the plants)
20 - 30% water changes usually every week to 1 1/2 week
tank temperature - 84 degrees F (heaters and chiller)
animals: 6 discus, 72 other fish (tetras and oto cats) and 4 Amano shrimp
KNO3 - 11.5 PPM added every other day
KH2PO4 - 1.955 PPM every other day
CSM + B - added on alternate days
sump: bioballs, mangroves (light on at night), mechanical filter pad and sponge
we kept water flowing over the bioballs during the tank repair
I add about 6-7 tsp. of baking soda per water change for the KH.