Water Boatmen....ALREADY!!

[Bigshooter920]

I've had my 8500 gallon Intex up and running for about 3 weeks now. This past week I went through the process of acid and aerate to lower the TA so that I could introduce Borates. I added the acid and Borax yesterday afternoon. Swept the pool thoroughly 3 or 4 times. I tested my levels last evening and everything seemed GTG. I then put the solar cover on for the first time this year. This morning my wife checked the pool temp and found boatmen in the pool!!! After one night of the cover being on?!?! I use an SWG and have been running my filter and backwashing frequently (as needed). Anyone have suggestions??
Levels as of last night;
FC: 5
PH: 7.4
TA: 70
CYA: 70
Borate: No test but should be around 50
CH: 260

 

[JoyfulNoise]

Brush the walls vigorously. Boatmen and backswimmers (there is a difference) lay their eggs on vertical surfaces (walls) in small groups. They are hard to see but obvious when you find them as they will usually be clustered. Knocking them loose and then vacuuming them up is the only way to ensure they be gone. Unfortunately the eggs and insects are fairly immune to chlorine.

Boatmen feed on algae and aquatic plants while backswimmers are predatory and eat smaller insects (and give painful stinging bites to humans). Both will die from lack of food but it can take a while.