Algae on rocks and cloudy water after cleaning sponge


Feb 3, 2017
Hello, I have 2 problems.
I have a 40 gal tank with a Fluval 70 hob filter
I have a 20ppi pre filter on the intake tube. I don't know if I even need yo use a prefilter??
I also put a small piece of Pinky filter on the top of the bio bag. Again, I don't know if this is necessary?
I have a small in the tank filter that I use with filter floss. I have to change the filter floss every week. I have this in to help with circulation.
My light is a Twinstar 900s led
I use CO2 injection
My substrate is Fluval Stratum and Seachem aqua sand. The sand is in the open area of the tank.

This is a new set up that's 5 weeks old. But, I've had this issue with cloudy water for several months on my old set up.

The first problem.
After a few weeks my water starts to get cloudy. I've been told to rinse the sponge out with tank water. When I do that I can't really get the sponge very clean. when I put the sponge back in it seems to get even more cloudy, or at least it stays the same as before I cleaned it.

If I rinse the sponge out with tap water I'm able to get it very clean. But every one says not to do that.
I know that using tap water will kill the beneficial bacteria.
I was wondering if after rinsing it in tap water I should soak the sponge in treated tap water before I put it back in the filter? At least that would remove the chemicals from the water.

The second problem.
I just started to dose the E I method on the 14th of Oct. 15mil of N and P 3 days a week.
I'm dosing the Mics at 5.5 mil 3 days a week. The reason the mic is 5.5 is because I had a mix with 40 grams that I was going to use when I was dosing the PPS PRO method.
I went to the aquarium calculator to get the numbers right.
The ppm for KNO3 per dose is 7.5 - KH2PO4 1.3 ppm - CSM+B for the FE is 0.2 ppm
I'm having an algae problem. There's algae on the rocks and the drift wood. I think I have good circulation. The plants are doing pretty good as far as I can tell. They are pearling very well.
My led is on for 8 hours a day.
The CO2 turns on 1 1/2 hours before the lights go on and shuts off 1 hour before the lights go off.

I hope I can get this figured out one of these days. I've spent a lot of time and money on this tank.
I don't mind doing the maintenance.
I just want to be able to enjoy the fruits of my labor.