Bacterial bloom after dosing phosphate

grisban · Mar 9, 2026

Hi all, new reefer here,

recently i have been dosing phosphates as on my salifert it keeps bottoming out, and couple days ago i decided to increase the dosing as it was undetectable for 3 days straight, now i am dealing i with a minor bacterial bloom (water is cloudy). What can i do?

Tahoe61 · Mar 9, 2026

Try running some charcoal.

For members to further assist you please post specific chemistry values, specific brand of phosphate you used, and an image. It's difficult to be certain whether what you're seeing is an algae or bacterial bloom.

Welcome to R2R.

grisban · Mar 9, 2026

Tahoe61 said:
Try running some charcoal.

For members to further assist you please post specific chemistry values, specific brand of phosphate you used, and an image. It's difficult to be certain whether what you're seeing is an algae or bacterial bloom.

Welcome to R2R.

water is a bit cloudy, my frogspawn and hammerhead are okay, torch is sad right now,

ph ~8-8.2 (redsea)
nitrate 10ppm (redsea)
phosphate ~0.03-0.1 ppm (salifert)
salinity 1.025 sg

do you need more parameters?
I am running a little bit of carbon, but its 2 weeks old by now but i have very low bioload, only snails and corals for now, skimmer is off (never turned on really)

Randy Holmes-Farley · Mar 9, 2026

Bacterial blooms are not typically any concern except aesthetically and possible from low O2 is there is insufficient aeration.

grisban · Mar 9, 2026

Randy Holmes-Farley said:
Bacterial blooms are not typically any concern except aesthetically and possible from low O2 is there is insufficient aeration.

I have a wavemaker and the return pump aimed at the surface, should be enough right?

Tahoe61 · Mar 9, 2026

grisban said:
water is a bit cloudy, my frogspawn and hammerhead are okay, torch is sad right now,

ph ~8-8.2 (redsea)
nitrate 10ppm (redsea)
phosphate ~0.03-0.1 ppm (salifert)
salinity 1.025 sg

do you need more parameters?
I am running a little bit of carbon, but its 2 weeks old by now but i have very low bioload, only snails and corals for now, skimmer is off (never turned on really)

Nice tank!

I would just wait it out and discontinue dosing any products at this point. The chemistry values you provided look good.
You could change out the charcoal if you like.
If the tank doesn't clear in another day or so just bump this thread.

Randy Holmes-Farley · Mar 9, 2026

grisban said:
I have a wavemaker and the return pump aimed at the surface, should be enough right?

For this sort of bloom, I expect so, yes.

grisban · Mar 10, 2026

Update: yesterday was my weekly waterchange day so i did 10%, and i dosed AF lifesource too as part of the maintenance

Today the water is extra milky cloudy... Should I just wait it out? Should I also stop dosing phyto?

Randy Holmes-Farley · Mar 10, 2026

grisban said:
Update: yesterday was my weekly waterchange day so i did 10%, and i dosed AF lifesource too as part of the maintenance

Today the water is extra milky cloudy... Should I just wait it out? Should I also stop dosing phyto?

Why are you adding that product?

grisban · Mar 10, 2026

Randy Holmes-Farley said:
Why are you adding that product?

Read good reviews of it online and my corals look happy after dosing it

Ive been dosing this for weeks

exnisstech · Mar 10, 2026

No help really except to say I dose PO4 and phyto and neither cause my water to become cloudy. Tank looks very new. I like to let new tanks settle in for several months before trying to make changes. Adding a bunch of stuff when a tank is young just turned into a roller coaster ride when I tried it early on. Looking at your test results I would step back and add absolutely nothing. I see know reason that tank couldn't be sustained with water changes only for the time being.