High Nitrates 75ppm +

Outatime · Aug 20, 2025

Hey all

Need some help please, have a proclear 230g setup, I had a lazy period with my tank I was going through some rough times and I wasn't able to do much apart from the basics with my tank then I went away on work for a month and my Refugium pump failed and I lost a bunch of fish inc my large puffer, the puffer was a **** machine and made a lot of waste which might be part of my nitrate issue.

Yesterday I did a 75% water change yesterday, I have a Naso Tang and 2 clowns in the tank as far as livestock goes and a lot of rock, I have cleaned everything up and vacuumed out the Refugium as there was a bunch of detritus/dead algae in there.

I have a Reefmat 1200
Reef Octopus Regal 250 INT
and a UV Light.

Can anyone suggest someway to lower the nitrates in my tank please, the hanna meter almost started smoking when I just did my test a moment ago and it read 75 ppm and blinking!

Thank you

Stu

KrisReef · Aug 20, 2025

Get back into regular maintenance, meaning i do a routine water change in a week or a month, whatever and let them fall as they might. You just did a huge intervention which is good enough for fishes. Changing things to any faster comes with additional risk, and the fish you have are fine with 76ppm nitrate, or else they would be dead?

Reef_at_Sea · Aug 20, 2025

Water changes are the fastest method of lowering your Nitrates.
But make sure that you are able to remove Nitrates & phosphates before doing so... Else you would just fall into a endless cycle...

I would setup a water change plan if i was you, i'm sure someone can help you with this as i have never done multiple daily water changes to lower nitrates, only single 30% changes.

Randy Holmes-Farley · Aug 20, 2025

There are many ways to reduce nitrate. Since you already have a refugium, growing macroalgae in it can be a good way to go.

Have you measured phosphate?

Lasse · Aug 20, 2025

Have you measured NO2? Hanna is not as sensitive to NO2 interference when measuring NO3 as many other kits are – but there is an interference.

Sincerely Lasse

Outatime · Aug 20, 2025

Thank you guys , phosphate is pretty high too at .90+ on the hanna, I will start on the water changes. Anything else I can do to speed it up? With only 3 fish I don't anticipate a lot of waste. If I was to move the livestock for a short time is there any faster way of dealing with it? Thank you again

The Gas Man · Aug 20, 2025

Implement a water change program for a while; personally I like smaller more referent changes than large water changes. Review your clean up crew and add if it makes sense especially if you have messy waters that won’t eat the clean up crew.

Randy Holmes-Farley · Aug 20, 2025

Outatime said:
Thank you guys , phosphate is pretty high too at .90+ on the hanna, I will start on the water changes. Anything else I can do to speed it up? With only 3 fish I don't anticipate a lot of waste. If I was to move the livestock for a short time is there any faster way of dealing with it? Thank you again

IMO, water changes are going to be expensive and tedious in this size tank, and will not drop phosphate all that much.

KrisReef · Aug 20, 2025

Outatime said:
Thank you guys , phosphate is pretty high too at .90+ on the hanna, I will start on the water changes. Anything else I can do to speed it up? With only 3 fish I don't anticipate a lot of waste. If I was to move the livestock for a short time is there any faster way of dealing with it? Thank you again

You are welcome.

What is the motivation for making these parameters "better," & better faster? You have begun improving the collected detritus and reported making good progress in that direction. If you do a 100% water change you can get the nitrate and phosphate close to zero, and adjust the alkalinity and pH and calcium to be the target numbers that you think will be perfect. Then, two days from now you can measure the phosphate and find that it went from zero back towards 0.9ppm again as it migrates from the substrate into the water column while all the other numbers move less dramatically away from the perfect target concentrations that you made today.

The key to getting things stable is persistance, not instant changes.

BryanM · Aug 20, 2025

Water changes work for nitrates pretty well, but they usually only temporarily lower phosphates.

You'll want a different strategy for lowering phosphate. What worked for me was a GFO reactor.

Outatime · Aug 20, 2025

Thank you, I know some of you recommended smaller water changes but if I did a few larger ones to start with to see if I can at least get it to a hanna readable level rather then try smaller changes? I wasn't really looking at the phosphate levels yet rather trying to lower the nitrates so I can add some corals at some point....understand no rushing it though.

Right now I have my lights off too so not to encourage growth in the main tank but would cheato in the sump be a good idea again? I think last time I didn't remove anything and it caused more problems I thought the more was better was the approach as it grew. I have made so many mistakes :-(

Going back to the live stock I only have 3 fish no cleanup crew or any corals or inverts, if I move them to a small tank and did larger water changes often would that be a good move?

Thank you

BryanM · Aug 20, 2025

Outatime said:
Thank you, I know some of you recommended smaller water changes but if I did a few larger ones to start with to see if I can at least get it to a hanna readable level rather then try smaller changes? I wasn't really looking at the phosphate levels yet rather trying to lower the nitrates so I can add some corals at some point....understand no rushing it though.

Right now I have my lights off too so not to encourage growth in the main tank but would cheato in the sump be a good idea again? I think last time I didn't remove anything and it caused more problems I thought the more was better was the approach as it grew. I have made so many mistakes :-(

Going back to the live stock I only have 3 fish no cleanup crew or any corals or inverts, if I move them to a small tank and did larger water changes often would that be a good move?

Thank you

Water changes to lower nitrates is a perfectly fine plan.

I did not like the sprawl of chaeto, so I went with a Santa Monica Algae Turf Scrubber, a fuge in a box on steroids.

Randy Holmes-Farley · Aug 20, 2025

Outatime said:
Thank you, I know some of you recommended smaller water changes but if I did a few larger ones to start with to see if I can at least get it to a hanna readable level rather then try smaller changes? I wasn't really looking at the phosphate levels yet rather trying to lower the nitrates so I can add some corals at some point....understand no rushing it though.

Right now I have my lights off too so not to encourage growth in the main tank but would cheato in the sump be a good idea again? I think last time I didn't remove anything and it caused more problems I thought the more was better was the approach as it grew. I have made so many mistakes :-(

Going back to the live stock I only have 3 fish no cleanup crew or any corals or inverts, if I move them to a small tank and did larger water changes often would that be a good move?

Thank you

I personally would not do water changes without knowing the magnitude of the problem. Even after changing 100 gallons all at once you may be very high.

To get a reading, mix 9 parts new salt water with 1 part tank water. Test it, then multiply the value by 10.

Outatime · Aug 20, 2025

Randy Holmes-Farley said:
I personally would not do water changes without knowing the magnitude of the problem. Even after changing 100 gallons all at once you may be very high.

To get a reading, mix 9 parts new salt water with 1 part tank water. Test it, then multiply the value by 10.

Thank you Randy.

Just did this and I got 6.9 so 69 ppm is my Nitrate reading!

Randy Holmes-Farley · Aug 20, 2025

Outatime said:
Thank you Randy.

Just did this and I got 6.9 so 69 ppm is my Nitrate reading!

Then I personally would not do huge water changes. Some great tanks have nitrate that high, and my target range is 5-50 ppm.

I’d get your refugium working again to have ongoing export.

Outatime · Sep 6, 2025

Hi again all

So two and a half weeks later, I have done a couple of water changes, cleaned my sump and all equipment , added a algea scrubber a few days ago, have a reactor with bio pellets in it and I just did a test a moment ago, still at 75ppm. The Hanna checker isn't flashing now so I guess thats good but is there any other suggestions? I am getting green hair algae creeping in on the rocks now...feel like I am going backwards again :-( I have a bottle of No Pox, should I give this a try? Last time I used it a year or so ago I had a lot of fish includding the puffer who was crapping a lot and it seemed to cause a bacterial smell in the tank hoping this time might be a little different. Apricate any advice? Just a reminder its a fish only tank right now.

Thank you again