I think I need to do more to eliminate phosphates

[rhitee93]

My phosphates keep creeping up even though I have to dose nitrates. This week my phosphates hit 0.43ppm, and I'm thinking about trying lanthanum chloride, or setting up a GFO reactor. Obviously I need to figure out where the phosphates are coming from, but I'm feeling nervous that I need to act to reduce the level in the meantime.

Factual stuff:

• 120gal display w/sump (108 gal of actual water volume)
• I do a 10% water change every week
• I use an 8-stage RO/DI system to for my water (sediment, 2 carbon, RO, Cation, Anion, and two mixed bed DI) Water reads 0TDS.
• Livestock: Foxface Rabbitfish, Tomini Tang, 2 Clowns, 1 Very small green spotted puffer, 13" snowflake eel
• I almost exclusively feed San Francisco Bay brand frozen foods (I have a variety that I pick rom at random)
• I feed the fish 2 cubes a day
• The eel gets fed 2 ro 3 times a week - scallops, squid, shrimp, salmon that I get from the fish counter
• The only coral is a GSP colony that is growing like crazy (I just added a Duncan and Frogspawn, but they've only been in the tank a few days)
• The tank is about 6 months old
• roller mat, Reef Octo Regal 150-int skimmer, small chaeto ball in fuge, but the photoperiod is very short because of the nitrate issue

Stuff I think is true, but I don't know for sure:

• I am thinking that lack of filtration isn't the issue since I am having to dose nitrates to maintain 10.0ppm. I have to add about 3ppm worth of sodium nitrate each week.
• I haven't been rinsing my frozen food and I'm wondering if that is the phosphate source. (How do you rinse what is effectively mush?)

Am I panicking for no reason? My phosphates hung out at 0.15ppm for 3 or 4 months. They took a big jump a few weeks ago, and then have gone up by about 0.050 a week for the last few weeks. I don't really know what has changed, but I feel like I need act to reduce the levels while I figure out the cause.

 

[rennjidk]

Either option will be effective in reducing and maintaining phosphates. Just pick whichever option seems easier for you. I don't believe rinsing your food is adding any detectable amount of Po4.

 

[Koty]

Did I miss somthing? You do not dose carbon?

 

[rennjidk]

Am I panicking for no reason? My phosphates hung out at 0.15ppm for 3 or 4 months. They took a big jump a few weeks ago, and then have gone up by about 0.050 a week for the last few weeks. I don't really know what has changed, but I feel like I need act to reduce the levels while I figure out the cause.

If I had to take an educated guess, since you're at the 1 year mark in such a large system and haven't made any changes to nutrient import, it's possible that you're finally hitting the crest of the phosphate binding ability of the rocks and substrate. I have absolutely no idea if that's true or not. One of the chemistry folks would need to chime in for an actual answer.

 

[rennjidk]

Did I miss somthing? You do not dose carbon?

He's already dosing nitrate. There wouldn't be a reason to, unless he's trying to cultivate bacterial populations for filter feeders. Po4 is better controlled through other means.

 

[stevemillersreef]

My phosphates keep creeping up even though I have to dose nitrates. This week my phosphates hit 0.43ppm, and I'm thinking about trying lanthanum chloride, or setting up a GFO reactor. Obviously I need to figure out where the phosphates are coming from, but I'm feeling nervous that I need to act to reduce the level in the meantime.

Factual stuff:

• 120gal display w/sump (108 gal of actual water volume)
• I do a 10% water change every week
• I use an 8-stage RO/DI system to for my water (sediment, 2 carbon, RO, Cation, Anion, and two mixed bed DI) Water reads 0TDS.
• Livestock: Foxface Rabbitfish, Tomini Tang, 2 Clowns, 1 Very small green spotted puffer, 13" snowflake eel
• I almost exclusively feed San Francisco Bay brand frozen foods (I have a variety that I pick rom at random)
• I feed the fish 2 cubes a day
• The eel gets fed 2 ro 3 times a week - scallops, squid, shrimp, salmon that I get from the fish counter
• The only coral is a GSP colony that is growing like crazy (I just added a Duncan and Frogspawn, but they've only been in the tank a few days)
• The tank is about 6 months old
• roller mat, Reef Octo Regal 150-int skimmer, small chaeto ball in fuge, but the photoperiod is very short because of the nitrate issue

Stuff I think is true, but I don't know for sure:

• I am thinking that lack of filtration isn't the issue since I am having to dose nitrates to maintain 10.0ppm. I have to add about 3ppm worth of sodium nitrate each week.
• I haven't been rinsing my frozen food and I'm wondering if that is the phosphate source. (How do you rinse what is effectively mush?)

Am I panicking for no reason? My phosphates hung out at 0.15ppm for 3 or 4 months. They took a big jump a few weeks ago, and then have gone up by about 0.050 a week for the last few weeks. I don't really know what has changed, but I feel like I need act to reduce the levels while I figure out the cause.

I started using the little discs that you put between the black blocks from maxspect. It was usually high at 40, now it’s at .02

 

[rhitee93]

No, I'm not dosing carbon. I don't even know how or why to do that yet. So much to learn in this first year...

If I had to take an educated guess, since you're at the 1 year mark in such a large system and haven't made any changes to nutrient import, it's possible that you're finally hitting the crest of the phosphate binding ability of the rocks and substrate. I have absolutely no idea if that's true or not. One of the chemistry folks would need to chime in for an actual answer.

I understand what you are saying, but I don't understand why the nitrates and phosphates are so disconnected. Both are generated from something I'm putting into the tank, so i would think they would both rise proportionally.

Maybe something is using up nitrates but not phosphates? Not sure what it would be. I don't have much algae growing, and not much in the way of coral yet.

 

[rennjidk]

No, I'm not dosing carbon. I don't even know how or why to do that yet. So much to learn in this first year...



I understand what you are saying, but I don't understand why the nitrates and phosphates are so disconnected. Both are generated from something I'm putting into the tank, so i would think they would both rise proportionally.

Maybe something is using up nitrates but not phosphates? Not sure what it would be. I don't have much algae growing, and not much in the way of coral yet.

Nitrates are more quickly consumed in most systems. You'll see a lot of tanks dosing nitrate, but few dosing phosphate once the system becomes saturated. The focus then shifts to phosphate removal.

I think you're searching for a flaw in your method that doesn't exist. So far, everything has been right on track as expected IMO.

 

[rhitee93]

Thanks for the insight. I've got some lanthanum chloride on the way. Based on what I've read, I'll start out slow to see how the system reacts.

 

[Randy Holmes-Farley Verified Community Expert]

Obviously I need to figure out where the phosphates are coming from, but I'm feeling nervous that I need to act to reduce the level in the meantime.

Answer: foods.

There's no need to panic, but lowering it is a fine plan. I choose GFO in my system.

 

[rhitee93]

I experimented with GFO some in the last week, but I just put a few spoonfuls (maybe 1/4 of a cup) in a mesh bag and placed in a high flow part of the sump. I took a very timid approach because I have read so many stories about GFO crashing phosphates to zero quickly. However, the bag of GFO has done nothing to my levels.

It sounds like this is a pretty common experience, and that most feel GFO needs to go in a reactor to be effective. If that is the case, I think I'll try the lanthanum chloride first.

 

[Koty]

I would strongly recomend carbon dosing just to feed the bacterial population. There are some that claim that carbon dosing help corals uptake phosphate. My nitrate is around 0 so I dose both amino acids and carbon as my phosphate is relatively high (0.2-0.1). Bottom line corals are very happy.

 

[rhitee93]

I would strongly recomend carbon dosing just to feed the bacterial population. There are some that claim that carbon dosing help corals uptake phosphate. My nitrate is around 0 so I dose both amino acids and carbon as my phosphate is relatively high (0.2-0.1). Bottom line corals are very happy.

Thanks! This is something I want to learn about. When I first got back into reefing I saw a post somewhere that talked about carbon dosing being dangerous if done wrong, and not for beginners, so I sort of filed that way for another day, and simply haven't explored it yet.

I'm just starting to add corals now, and will have to up my aquarium chemistry knowledge. I haven't worried about the reef chemistry much up to this point as I was focused on just keeping fish happy.

 

[Koty]

I use carbon dosing reagents from Tropic Marine. They do a great job IME. I have a lot of fish so I use Elimi NP dosed 4 x 1.5 ml /day in 110g and Reef actif once a week. Once nitrates hit 0 I started dosing amino acids. I do not see the point of dosing nitrates in a high bioload tanks as it is probably low but not real 0.

 

[Koty]

A happy Trachyphylia at night:

My 2y old Elegance coral

 

[rhitee93]

...My 2y old Elegance coral ...

Nice! I'm thinking an elegance will be my next addition.

 

[Koty]

Nice! I'm thinking an elegance will be my next addition.

For Elegance I would wait for your tank to be about 1 y old.

 

[rhitee93]

Ahh, bummer. I thought they were more hardy than that. I may have to wait until summer then.