25 gallon aio, cyano problems!

Kbnano · 2026-10-02T19:09:49-0400

I am getting tired of dealing with this. Sorry, if it isn't this then it's been something else. I've had a small tank for many years and they're not easy. I now for the last 3 or so years have the 25 gallon aio. I've tried almost everything thru the different problems. So now I was going to use chemi clear and flush this stuff out. Cyano I believe. Now I was ready to do this and read something else that said not to. Well, I've taken the rock out before and all that as well, not ready for that now. Here are some pics for any help.
Thanks.

EnterName · 2026-10-02T19:14:53-0400

To me it looks more like green hair algae problem and maybe some diatom stains on the substrate. Are you buying water from an LFS or do you have your own RO/DI system? Maybe it's letting silicates through that feed diatoms. It's also possible you have a sand-dwelling dinoflagellate issue (the community would probably refer to it as "Large Cell Amphidinium", a microscope can help with the identification)

Kbnano · 2026-10-02T19:26:01-0400

EnterName said:
To me it looks more like green hair algae problem and maybe some diatom stains on the substrate. Are you buying water from an LFS or do you have your own RO/DI system? Maybe it's letting silicates through that feed diatoms. It's also possible you have a sand-dwelling dinoflagellate issue (the community would probably refer to it as "Large Cell Amphidinium", a microscope can help with the identification)

I get from my store, but I also now have rodi water filter home. I had started a few months ago with bubble algae, that was fun. Then hair algae, but sand bed drives me crazy. The rock has gotten out of control. I'm using a master all the time, have hand picked as much as could, I had a huge denial on the rock that ended up dying when I took the rock out in my changed tank water to spot treat but it wasn't great. And then different problems emerged. Fish don't seem to care but whats left of my Itty corals do. And it looks bad.

Kbnano · 2026-10-02T19:27:58-0400

EnterName said:
To me it looks more like green hair algae problem and maybe some diatom stains on the substrate. Are you buying water from an LFS or do you have your own RO/DI system? Maybe it's letting silicates through that feed diatoms. It's also possible you have a sand-dwelling dinoflagellate issue (the community would probably refer to it as "Large Cell Amphidinium", a microscope can help with the identification)

I get from my store, but I also now have rodi water filter home. I had started a few months ago with bubble algae, that was fun. Then hair algae, but sand bed drives me crazy. The rock has gotten out of control. I'm using a master all the time, have hand picked as much as could, I had a huge denial on the rock that ended up dying when I took the rock out in my changed tank water to spot treat but it wasn't great. And then different problems emerged. Fish don't seem to care but whats left of my Itty corals do. And it looks bad.

Kbnano said:
I get from my store, but I also now have rodi water filter home. I had started a few months ago with bubble algae, that was fun. Then hair algae, but sand bed drives me crazy. The rock has gotten out of control. I'm using a master all the time, have hand picked as much as could, I had a huge denial on the rock that ended up dying when I took the rock out in my changed tank water to spot treat but it wasn't great. And then different problems emerged. Fish don't seem to care but whats left of my Itty corals do. And it looks bad.

Baster* xenia coral not denial*

EnterName · 2026-10-02T19:35:28-0400

Kbnano said:
I get from my store, but I also now have rodi water filter home. I had started a few months ago with bubble algae, that was fun. Then hair algae, but sand bed drives me crazy. The rock has gotten out of control. I'm using a master all the time, have hand picked as much as could, I had a huge denial on the rock that ended up dying when I took the rock out in my changed tank water to spot treat but it wasn't great. And then different problems emerged. Fish don't seem to care but whats left of my Itty corals do. And it looks bad.

Do you happen to have a TDS meter? The RO/DI water of your system should show 0ppm TDS or if you are using a conductivity meter below 1µS/cm. There are also "inline" TDS meters you can connect to the outlet of your RO/DI system which is a pretty good way to tell if your DI-resin needs to be replaced. Silicates are one of the first things to come through and fuel diatom growth.

There are also test kits for Si/SiO₂/SiO₄ (e.g. from Salifert) but I'm not too sure about their accuracy (Randy will know better) and their detection limit is quite high. You could also get an ICP test to check.

Alternatively, you can try to find a cheap compound microscope (not a digital one) so we can look at the substrate more closely. Diatoms and Dinoflagellates are sometimes a bit challenging to tell apart without taking a closer look.

If it turns out to be a dinoflagellate issue, I could imagine it will resolve itself once the green hair algae is dealt with.

Kbnano · 2026-10-02T19:45:27-0400

EnterName said:
Do you happen to have a TDS meter? The RO/DI water of your system should show 0ppm TDS or if you are using a conductivity meter below 1µS/cm. There are also "inline" TDS meters you can connect to the outlet of your RO/DI system which is a pretty good way to tell if your DI-resin needs to be replaced. Silicates are one of the first things to come through and fuel diatom growth.

There are also test kits for Si/SiO₂/SiO₄ (e.g. from Salifert) but I'm not too sure about their accuracy (Randy will know better) and their detection limit is quite high. You could also get an ICP test to check.

Alternatively, you can try to find a cheap compound microscope (not a digital one) so we can look at the substrate more closely. Diatoms and Dinoflagellates are sometimes a bit challenging to tell apart without taking a closer look.

If it turns out to be a dinoflagellate issue, I could imagine it will resolve itself once the green hair algae is dealt with.

I do not have a meter, this is a fairly new system, couple months. I use it mostly top off. I use the store water mostly for water changes and adding. I think Im too picky about always wanting white clean sand but it shouldn't look like this. I will check on meter or test. It is new though. Have had green hair algae before and often. Just seemed different this time. Color and all over the back wall I scrape off. Constant sucking it out however I can, but its too much.