Can't figure out what exactly is wrong with my tank

[pomoev]

Hi reefers,

I'm looking for some advice on what's going on with my tank. I think I brought most parameters to proper levels, but the new LPS/SPS frags still deteriorate quickly.
The tank is RedSea 525XL which I started a year ago. It was a rollercoaster up until this October when I finally had enough time to fix things. For the last couple months I maintain pretty steady levels at:
Calc: ~440
Alk: 8.4
Mg: 1600+ (my RedSea magnesium test has expired recently, so maybe this is wrong)
Nitrates: 1-2
Phosphates: 0.35
PH: 7.85-8.05 (it's around 8 during the day, but drops very quickly to ~7.85 when the lights turn off, then slowly climbs up to 7.95 during the night).

I use Red Sea blue bucket salt, and dose Reef Fusion two-part (very little, under 10ml of each daily). I run a skimmer and do 10% water changes every 1 or 2 weeks. I also run a refugium with chaeto on a reverse schedule, and it grows pretty well.
Regarding bioload:
- 4 bigger tangs (4-5inch),
- about 10 smaller fishes like bar dartfish, clowns, gobies, and such. I feed them TDO 3 times a day plus 2 cubes of mysis.

With regards to corals, I had a huge polyp bailout in September that affected most of my acans and euphyllias, so I moved whatever I could save into my other tank. Currently, there are two fist-sized colonies of torch and hammer and a few smaller frags that somehow survived the previous months. I also have some softies that have been doing pretty well throughout all that time.

Now to the current situation. Now that the parameters are more or less stable and not terribly out of hand, I tried adding some favia and monti frags into the system, and they don't do well. Smaller frags deteriorate like this, where edges all get bare-bone, they stop feeding and slowly die off.

Some other observations:
- the live rock is mostly covered with short (turf?) algae, especially in well-lit areas
- coralline algae mostly grow on the back wall, and in the fuge

Tank photo:

Now to the questions:
- is 0.35 phosphate too bad?
- is pH a problem?
- can high Mg cause these troubles?
- what else am I missing?

Thanks and merry Christmas!

 

[shandoee]

I’ve seen some of my SPS and lps start to close up at around 0.27 ppm po4. So maybe the high phosphate is the cause.

pH is fine because my tank stays steady around 7.7-7.9 in a 24 hour time. But sps are just growing slower.

From my posts in the reef chemistry forum, high magnesium isn’t an issue for corals. My magnesium lately is in the high 1600’s (1668 as of now) on my apex. I use the salifert to confirm this number.

 

[pomoev]

I’ve seen some of my SPS and lps start to close up at around 0.27 ppm po4. So maybe the high phosphate is the cause.

pH is fine because my tank stays steady around 7.7-7.9 in a 24 hour time. But sps are just growing slower.

From my posts in the reef chemistry forum, high magnesium isn’t an issue for corals. My magnesium lately is in the high 1600’s (1668 as of now) on my apex. I use the salifert to confirm this number.

Thanks for the comment.
I didn't mention it in the post, but three days ago I used Brightwell Phosphate-E and dropped PO4 down to 0.27, where it's been staying so far. I guess I can go further this way.

 

[Pistondog]

Phospate e is lanthanum chloride, which can be harmful to tangs if not used cautiously. Use gfo below 0.5 ppm po4.
There is also Phosphate bound up in rocks and sand, not just water.

 

[pomoev]

Phospate e is lanthanum chloride, which can be harmful to tangs if not used cautiously. Use gfo below 0.5 ppm po4.
There is also Phosphate bound up in rocks and sand, not just water.

I poured 3.5ml from a syringe into a filter sock - was it cautious?
I have had about 300ml of phosguard in a filter sock for some time now. I haven't noticed any immediate effects of it, but it probably contributes to phosphates not growing back up.

 

[pomoev]

There is also Phosphate bound up in rocks and sand, not just water.

Is there a way to apply this information in the practice?

 

[Pistondog]

I poured 3.5ml from a syringe into a filter sock - was it cautious?
I have had about 300ml of phosguard in a filter sock for some time now. I haven't noticed any immediate effects of it, but it probably contributes to phosphates not growing back up.

The lc binds phosphate into a precipitate that is larger than 5 microns, so it can be filtered with a 5 micron sock. Being cautious is to minimize the amount of precipitate in the water at any one time to prevent clouding the water and potentially clogging some fish's gills.
I dose phosphate e diluted with rodi 50:1 into the overflow, caught by the 5 micron sock, over 3 or 4 hours.

 

[Pistondog]

Is there a way to apply this information in the practice?

Only when trying to determine how to reduce po4 levels. For example water changes are not considered particularly effective.

 

[pomoev]

The lc binds phosphate into a precipitate that is larger than 5 microns, so it can be filtered with a 5 micron sock. Being cautious is to minimize the amount of precipitate in the water at any one time to prevent clouding the water and potentially clogging some fish's gills.
I dose phosphate e diluted with rodi 50:1 into the overflow, caught by the 5 micron sock, over 3 or 4 hours.

This is very interesting, thank you.

 

[Tim McLellan]

What I've seen/heard is that pellets like TDO tend to increase PO4, so maybe shift more to the frozen foods. Mine was high so I tried that. Didn't make a huge difference but it has come down a little.

 

[moz71]

How much did you phosphate drop when you add the phos E? Over what period? I had a problem when I did this too fast!

 

[pomoev]

How much did you phosphate drop when you add the phos E? Over what period? I had a problem when I did this too fast!

Mine dropped from 0.35 to 0.26. I measured the difference in ~5 hours after dosing. I didn't notice any issues.

 

[Spare time]

0 nitrate and high phosphate is a bad combo. First thing to do would be to rise nitrate and lower phosphate. You can mix a bag of carbon and gfo together into a very fine mesh bag and place it in a sock for a few days.

 

[moz71]

Mine dropped from 0.35 to 0.26. I measured the difference in ~5 hours after dosing. I didn't notice any issues.

Yea that’s not it! The only thing I can think of is did you ever get an icp test? Any heavy metals? Or minor elements lacking.

 

[pomoev]

0 nitrate and high phosphate is a bad combo. First thing to do would be to rise nitrate and lower phosphate. You can mix a bag of carbon and gfo together into a very fine mesh bag and place it in a sock for a few days.

1. My nitrates are in 1-2 range.
2. Do you think phosphates are the root cause? I'm already working on it.

 

[Lavey29]

1. My nitrates are in 1-2 range.
2. Do you think phosphates are the root cause? I'm already working on it.

Nitrate should be 5 to 10 for coral nutrition

 

[dedragon]

Nitrate should be 5 to 10 for coral nutrition

^ increase water changes and filter sock or media change out frequency, to get nitrates and phosphates down by about half. Also i would maybe run a simple diy co2 scrubber for your protein skimmer to increase pH and make it more constant (if monitoring pH)

 

[dedragon]

works with any food safe container

 

[pomoev]

Yea that’s not it! The only thing I can think of is did you ever get an icp test? Any heavy metals? Or minor elements lacking.

I did ICP tests in October. Only cobalt, iron and zinc were below the recommended values, but I started doing water changes more often and I think these elements should have been replenished. Should probably do another test, that's always a good idea, thanks.

 

[dedragon]

its more likely the phosphate, and pH. I would also check forums for par levels using your light it may be set too strong right now, gl and happy holidays