hoppycalif

Several times I have seen in threads here, a request for how much Fleets Enema to dose for phosphate. Each time it is pointed out that the fertilator is incorrect for this source. So, I did some research and calculation and came up with the following:

I currently dose 1/16 tsp of KH2PO4 in my 29 gallon tank (25 gallons of water). That gives me 250 mg of phosphate per dose. I sometimes increase this if I get green spot algae, so the amount is about right for that much water and the 3.8 watts per gallon I use. To calculate an equivalent dose of Fleets enema:

Fleets contains about 130 mg PO4 per ml of solution, based on a thread here and based on my calculations. (Actually my calculations say it is more like 170 mg per ml, because I am assuming the percentages given on the bottle of enema are based on non-hydrated sodium phosphates, and the 130 is based on the hydrated form.) Using 130 mg per ml is close enough for our purposes.

If we want 250 mg of phosphate we need 250/130 ml of Fleets, or about 2 ml, which is about 30 to 40 drops of Fleets. So, for 25 gallons of water 30 to 40 drops or 2 ml of Fleets Enema will be a good dosage for EI, 3 times a week dosing, for phosphate. For other tank sizes, scale this up or down by the ratio of your tank water volume divided by 25.