Red algae/ yellow water issue

[LMurphy]

Hi all,

Help!!

I’m after some advice as I’m really struggling with no idea on how to fix.

I started a saltwater fish tank in September 2024 and cycled it through.

At first I had a green algae issue which I managed to overcome.

However, now I have yellow looking water and a red algae bloom. My pH, nitrites, ammonia are all in parameter however my nitrates and phosphate is reading 0 and have done for some time. I have been feeding daily to try raise the levels but still staying at 0. I tried not changing the water but it just went worse and worse. So at the moment I am changing the water every 5 days. Day 1/2 still shows some yellow water but by day 5, it’s back to what it was.

I’ve turned the lights down aswell in case that was the issue but to no avail.

I have a reef mat, a protein skimmer and carbon reactor however it’s not clearing up at all.

Any advice?

 

[Dan_P]

Hi all,

Help!!

I’m after some advice as I’m really struggling with no idea on how to fix.

I started a saltwater fish tank in September 2024 and cycled it through.

At first I had a green algae issue which I managed to overcome.

However, now I have yellow looking water and a red algae bloom. My pH, nitrites, ammonia are all in parameter however my nitrates and phosphate is reading 0 and have done for some time. I have been feeding daily to try raise the levels but still staying at 0. I tried not changing the water but it just went worse and worse. So at the moment I am changing the water every 5 days. Day 1/2 still shows some yellow water but by day 5, it’s back to what it was.

I’ve turned the lights down aswell in case that was the issue but to no avail.

I have a reef mat, a protein skimmer and carbon reactor however it’s not clearing up at all.

Any advice?

Hi! The yellow water looks like micro algae bloom, possibly a dinoflagellate bloom. I have seen this in my experimental brightly lit aquaria with no filtration only water changes and weak circulation. I list all parameters because I can’t say if anyone is more important than others. The systems are also nitrogen and phosphate depleted. For my aquaria, phytoplankton blooms are uncommon but not impossible. Because this is a phytoplankton bloom, maybe a UV would help end the bloom although the animal husbandry practices you follow might need adjusting too.