Help with nitrates/phosphates

[11f150]

My tank has been up for about a year and half now. Up until about 2 months ago it was FOWLR. During that time I usually fed my fish once a day and did regular maintenance. Since then I've decided to get back into coral so I upgraded my lights and flow. I did notice however my nitrates and phosphates were very high and I'm not sure exactly why since I've never had a issue with them in previous tanks.

This week I did get pods and the refugium section going in my sump with macro algae. This was the first time pods have been introduced to my tank, along with macro algae since its been up but like I said before I never had an issue in the past with these levels so I never had pods/macro algae. Over the past month I probably have done 10 to 15 - 20% water changes.

Now this is the first tank I have had in our new house. Another thing to note is the water in the area I live in now goes through DI resin about every 2 weeks if I'm doing a lot of water changes. So I'm not sure if its a water issue or not. Am I on the right track for levels to go down gradually? My tank is currently fallow due to seeing ich on one of my fish so they are in QT. So I want to correct this before they go back to the DT. I'm thinking about taking the sand out slowly as well. Maybe around 20% a week and go bb. I did have 2 wrasse's go missing probably 7-8 months ago. I looked for them everywhere (without upsetting the sand too much I went through it, around the tank if they somehow jumped out and somehow popped my screen top off). I'm not sure if they died while being under the sand and they are still giving off ammonia.

Thanks

Nitrates 80 ppm (API)
Phosphates .90 (hanna)

 

[Randy Holmes-Farley Verified Community Expert]

Nutrient issues are generally from foods, unless you are still cycling/curing rock that has dead organisms attached to it The focus should be on more export, and there are lots of ways to do it: macroalgae, ATS, phosphate binders, dosing organic carbon, denitrators, etc. Water changes are not usually the best way, but they can help.

These have more:

Phosphate In The Reef Aquarium
https://www.reef2reef.com/blog/?p=3184

Nitrate in the Reef Aquarium - REEFEDITION
https://www.reef2reef.com/blog/nitrate-in-the-reef-aquarium

 

[Larry L]

You mentioned DI resin but are you also using an RO unit? If not, putting one in front of your DI would help get rid of a lot of impurities instead of making the resin handle it all. If you are using an RO unit, might need to change the membrane and/or prefilters since it must be leaving a lot of stuff in the water that the DI resin has to handle.

Also should probably check nitrates/phosphates in the water you are using to mix salt and to top off - if those are high then doing more water changes won't help. I agree with Randy that other ways of doing nutrient export will probably work better than water changes.

 

[11f150]

Yes it’s a rodi unit. I change all filters and do resin at the same time so nothing is old. I flush the membrane as well quite a bit. The water here has always been like that. I do need to test my rodi water which I will do today. I am going to step up my nutrient export after I decide which way I want to go.

 

[Larry L]

It still sounds to me like maybe something is up with your RO unit if you are burning through DI that fast. For example if you have a lot of chlorine or chloramine in your source water, and don't have a carbon block filter specifically designed to take those out, then they can degrade the RO membrane.

Have you measured the TDS of your water before the RO unit, after the RO but before the DI, and after the DI? The TDS after the RO unit should be less than a few percent of what's coming in from your water supply, and the TDS after the DI should basically be zero.

If you don't have a TDS meter, I'd recommend something like this: https://www.bulkreefsupply.com/triple-inline-tds-meter-trm-1-hm-digital.html

 

[11f150]

It still sounds to me like maybe something is up with your RO unit if you are burning through DI that fast. For example if you have a lot of chlorine or chloramine in your source water, and don't have a carbon block filter specifically designed to take those out, then they can degrade the RO membrane.

Have you measured the TDS of your water before the RO unit, after the RO but before the DI, and after the DI? The TDS after the RO unit should be less than a few percent of what's coming in from your water supply, and the TDS after the DI should basically be zero.

If you don't have a TDS meter, I'd recommend something like this: https://www.bulkreefsupply.com/triple-inline-tds-meter-trm-1-hm-digital.html

I don't know my TDS before the RO unit. My RODI unit does have a TDS meter on it but I believe only does after RO and after DI. I did just test my RODI water and its 0.00 phosphates.

@Randy Holmes-Farley I'm thinking on dosing NOPOX and running GFO until my levels are down to acceptable levels.