GHA problem... No phosphate or Nitrate???

[Richmond]

Good morning all... I've been dealing with a GHA problem for a few months.

My tank is an IM40. I run a single AI Prime HD (which probably isn't enough?) for 10 hours a day, but 2 hour of ramp up each way so only full strength for 6 hours. I have a filter sock in one overflow and a sponge inside a media basket on the other.

The first attempt I made was to add my skimmer back to the system (it had been offline for a year). This made no impact after 2 months so I took it back out.

Next I added an algae scrubber. This grew algae pretty okay, but had little impact.

Two weeks ago I added more clean up crew (which is probably still a little light) and currently have ~15 snails and ~10 hermits in a 40 gallon mixed reef with ONE clownfish and one cleaner shrimp.

So today I tested everything again... Below are the findings

pH - 8.04 (I'm working on raising this with kalk in ATO and need to make it a little stronger)
calcium - 420 (red sea test kit)
alkalinity - 10 dKH (red sea test kit)
nitrate - 0.00 (API test kit)
phosphate - 0.00 (tested with hanna checker)

I do feed "Coral Frenzy Coral Food" once a week and either mysis or pellets to the Clown every other day (small amounts).

Overall my bioload is TINY so I'm concerned about why the GHA is thriving. I've also recent setup an automatic waterchange system and I'm changing around 1.25 gallons per day (a small change every 3 hours).

Any thoughts, advice, or something I'm obviously overlooking?

 

[Sallstrom]

I think you can just wait for the CUC to do their thing. Maybe you could manually remove some hair algae, snails usually don't like to graze on longer hair algae. So if you help shortening the algae, the snails might get on with the grazing.
Maybe also get some more CUC. I think sea urchins are great, but there's plenty to chose from.

If you are so low in nutrients you might get Cyanobacteria, so my advice is also to try to get at least measurable values of NO3 and PO4.

Hope it works out

 

[Diesel]

Roll up the sleeves and start removing it manualy.
Your HA is consuming the No3 and Po4 before your test kit can detect any.
That’s why it’s undetectable when you test.
Yet you still have nutrients in your tank.
How long this tank has been setup?

 

[Randy Holmes-Farley]

How bad is the algae?

The API is not adequate to suggest there is not enough nitrate, and algae can thrive on ammonia as the nitrogen source anyway.

I'd look for a biological control (something that eats it).

 

[Richmond]

Roll up the sleeves and start removing it manualy.
Your HA is consuming the No3 and Po4 before your test kit can detect any.
That’s why it’s undetectable when you test.
Yet you still have nutrients in your tank.
How long this tank has been setup?

Tank is a little over 2 years old.

How bad is the algae?

The API is not adequate to suggest there is not enough nitrate, and algae can thrive on ammonia as the nitrogen source anyway.

I'd look for a biological control (something that eats it).

The algae isn't "that" bad. It's basically just kinda patchy here and there, worse in lower flow areas. Any suggestions on what would eat it other than snails? I do have two emerald crabs I forgot to mention earlier, but they've only been in the tank for a week.

 

[Randy Holmes-Farley]

Fish are usually the best bet, but its harder in a smaller tank.

What fish do you have?

 

[Richmond]

Fish are usually the best bet, but its harder in a smaller tank.

What fish do you have?

One lonely clown fish

 

[Idoc]

There are some algae that thrive on low nutrients and it's not a nitrate or phosphate issue. Just like @Randy Holmes-Farley said, some prefer ammonia as their food source. There's a 30+ min video in the BRS 52 weeks of reefing that talks about Nuisance algae and explains well how to approach different situations. Definitely worth the time to watch for info and ideas.