The mystery of two tanks... HELP!

[Tomorrow's Waters]

Okay everyone I have run into an interesting and difficult predicament that I think I need more information on.

So I have two tanks. Let's call them Tank 1 and Tank 2. Both tanks have been running for one year, both tanks have their own filtration systems with exactly the same equipment, and both tanks are reading zero nitrates (tested with NYOS) and around 0.1 ppm PO4 (Hanna Checker).

Here is where it gets interesting:
Tank 1 has only one six line wrasse, one peppermint shrimp, 5 LPS frags and about 1 pound of live rock per every 3 gallons of water (lightly stocked with very little live rock). In addition, Tank 1 has recently developed diatoms and is also slowly growing a thin layer of green algae.

Tank 2 has many fish of varying sizes (one is a very large domino), lots of invertebrates, a good amount of LPS corals, and probably more live rock than water in the tank (Heavily stocked with lots of live rock). Tank 2 is also COVERED in green algae.

Important notes: All corals are opening and doing well despite the algae, both tanks are 60 gallons, neither tank has a refugium, both tanks have the same feeding schedule (different amounts) and a very strict maintenance schedule.

My goal is to get the nitrates up to rid/prevent diatoms but lower the phosphates slightly to starve out the green algae and I want to do this in both tanks which are clearly very different. What do you all think is the best course of action here and why?

Thanks everyone!

 

[Jordan92595]

I would hold off on water changes because that will just spike your algae boom.
imo i think yo u should grab your siphon grab a filter sock and try to suck out as much of that algae as you can out of your tank into the sock but draining the water back into your tank through the sock. this will help you get that algae out without doing a water change which will feed your algae even more