Phosphate Stability Help

[WTJReef]

Struggling to pin down my phosphates…

Tank is approaching 1 year old. Had mature media from a previous tank.

For the past month I’m struggling to keep my phosphates stable. Started off with chaeto in a light reactor. Nutrients were low and stable. Found phosphates slowly rising a couple months back so started spot dosing LaCl into skimmer cup. Opened up light reactor to find chaeto decomposing so figured it was not getting enough flow coming off my manifold and cleaned out the reactor. Added a stronger pump but have not added chaeto back.

After I took out the chaeto, phosphates went from an average of 0.04-0.06 to 0.14 very quickly. At this point I added a bit of GFO to my media reactor and phosphates dropped to 0.00 within a few days along with a dip in alkalinity before heading back up to 0.1 within a couple weeks. Got burnt/bleaching tips on my sps and Monti plates, months have since recovered some SPS have not (yellow tenius, PC rainbow) all SPS were growing well and had encrusted.

I’m not sure about the chemistry behind the alk swing and GFO or how quickly it binds up phosphate but I’ve taken it out, I’ve never had good results with it and tried a product called phos zorb from API in the media basket under my filter roller. I’ve used it previously in my frag tank to good effect. Also running zeolite and carbon. Phosphates currently at 0.03

What are some solutions for keeping phosphate stable, am I doing something wrong? On my manifold, should I run Chaeto reactor before Zeo/carbon reactor? Both reactors return into sump.

I’d love for my phosphates to stay under 0.07-0.08 but more importantly I want them to be stable.

Everything else is stable

Current Parameters:

Salinity 1.025
pH 8.3
Alk 9.3
Calcium 430
Mag 1370
Nitrate 8.4
Phosphates 0.03

 

[ekandler]

Personally I’d investigate the source of those nutrients. Do you have a large quantity of fish relative to coral? What’s your feeding regime? Sounds to me like you need to feed less or dial in your feeding vs your export. I’ve had to adjust my fuge light schedule based on my feeding to ensure my tank was in equilibrium.

Personally, I avoid GFO. It works great when new and fades in its effectiveness as it’s depleted. So on day 1 it’s great, by day 10 it’s not so great. That inherently creates some instabilities. Reactors with a good amount of tumbling helps, but it’s still true regardless.

Between coral intake, skimming, a refugium/chaeto reactor, and water changes you should be able to manage nutrient export. GFO or supplements like PhosE should be used in emergencies, in my opinion.

 

[WTJReef]

Thanks for your advice,

I do primarily feed the aqua forest pellet food for convenience which I have heard is higher in phosphates. Maybe I should feed more frozen…

Fish load is decent with 3 tangs, two of them quite fat, and some other small fish but hasn’t really changed in the past 6 months bar a few chromis. I think I’m definitely at capacity and wouldn’t add more. Coral load is moderate several large LPS colonies and 7 larger encrusted SPS colonies. Lots of frags I was hoping to grow out

The reactor I have is AF110. Recently upgraded from the AF90. I have a bubble Magus reactor that sits in the sump, I previously used it on its own for GFO in my previous tank, but now it pushes water through some ceramic biomedia for me

I don’t have a fuge, had to sacrifice that when I modified the sump for the filter roller. I would love to get the algae reactor running, will give chaeto another go but want to avoid just having it decompose in the reactor again

 

[ekandler]

seems like you know what you’re doing, but I will say even the smallest things in this hobby that some people take for granted, actually require careful consideration.

For example, just feeding fish isnt that simple. I trialed a few different foods and combinations until I landed on what I use now, which is a mix of Hakari Marine A and PE Pellets in an auto feeder, feeding once a day, and a cube of frozen LRS reef frenzy every other day.

I had a similar issue to you, but my nitrates were tanking (with a thriving fuge) and my phosphates were spiking, and I figured out it was because of my pellet food. I was using a particular brand that was high in phosphate and my tank couldn’t handle it. So I played around until I found what worked for me and increased nitrates and phosphates evenly.

Maybe try experimenting with other types or brands of food. Every system is different, so it’s hard to say what will work for you without experimenting. Some people talk down on auto feeding pellets, but as long as you do it smartly it’s a great way to gain consistency.

 

[MrGisonni]

I feel you. For me it's been reef roids and un-rinsed mysis shrimp and a tiny bit of rowaphos. Trying to find a balance myself. The rowaphos works a little too quickly for my liking. When I add it, I see some corals stress a bit for a day or two.

 

[LobsterOfJustice]

Are you having algae issues? As you noted, trying to control the phosphates with GFO actually caused more problems (actual coral damage and death) than the high phosphates did. I’d just let them go for a bit and see where they stabilize. Don’t let the number itself scare you. You only need to solve the problem if it is actually causing a problem in the tank. Stability is more important than a particular number and you are causing instability by trying to control/lower it. Many people recommend approximately 1:100 ratio of PO4:NO3 which in your case would be a PO4 of 0.08.

I would try to get the Chaeto re-established for a long term resolution.