I’m using rodi 5 stage 75 gpd. Really need to change the filters, they’re in their way from brs. Po4 is .16 and dropping with phosphate-e. I test it with Hanna checker. It does get sunlight for a couple of hours a day. The new 300 gal will not be getting sunlight. I just want to handle this issue before I start up my new tank in the new house. If I can’t handle a 90 gal how can I handle a 300?Are you using RODI water or tap water from the faucet ?
What is your phosphate level and how are you testing ?
Is tank at or near a window?
add some snails such as :
Astrea
cerith
turbo grazer
trochus
A Pencil urchin
8-10 Caribbean blue leg hermits