My LPS aren't doing well. Need some help with my first tank.

[CapnWreckz]

I'll get the tank stats out of the way first.

20 Gallon Cube AIO with AI Prime 16HD running on David Saxby preset. It's about 6 months old (not including the cycle), and for the first few months everything was going well, corals were completely open and growing, and now pretty much all of my LPS is shrunken with low polyp extension. None of them have died, but they aren't opening all the way nor are they growing. My soft corals are all doing great.

My Hammer, Torch, Alveopora, Blasto, Candy canes, and Duncan are all smaller than they used to be and not doing well. My Acans are fine, though.

My Ricordea and Rhodactis mushrooms, GSP, Zoanthids and Palys, Clove Polyps, Green leather toadstool, and Kenya Tree are all doing very well and growing.

This has been going on for around 2 months, the previous 4 months before that everything was happy.

Nitrate: 10ppm
Phosphate: 0ppm
Magnesium: Over 1500
PH: 8-8.15
Alk: 8.6DKH
Temperature: 78deg Farenheiht
Salinity: 1.024

For water changes I've always used distilled water. I do a 25% water change around once a month, and I feed my corals once a week with reef-roids. I also dose amino acids.

I'm honestly not sure what the problem is, maybe it's my non-existent phosphates? Truly I have no idea why they're so low. My tank is overstocked to be honest, with 6 (small) fish in 20 gallons, and plenty of hermit crabs and snails. I feed quite a lot, around 2-3 times a day, both frozen and pellet foods.

In an effort to raise my phosphates I removed the Chemi-pure Blue (which I had because I heard that you need to run carbon because of toxins that leather corals release) and the majority of the Chaeto I have growing in the rear compartment of the tank around a month ago, but I still haven't seen an increase in phosphates.

Truly I don't even know if the phosphates are the problem but the rest of my parameters look perfectly fine to me, although I am definitely a beginner and not as knowledgeable about these things as most of you are.

As an example I'll post a picture of my hammer from 2 months ago, and a picture of what it currently looks like.

Any help would be appreciated. I've grown a love for this hobby and I'd like to be successful with my tank, though I understand that nothing good happens fast.

 

[colejr]

I lost a handful of LPS when my Phosphates bottomed out.

 

[CapnWreckz]

I lost a handful of LPS when my Phosphates bottomed out.

How did you raise your phosphates afterwards?

 

[muzikalmatt]

At first glance, I would definitely think the 0 phosphates is your issue. Corals need nutrients to survive (nitrates and phosphates) so if your phosphates have been bottomed out for a while, it could lead to these issues.

As far as how to raise them, feeding more doesn't always work as you need to be feeding a food that is higher in phosphates (stuff like reef roids and some frozen foods are typically high in PO4). Removing the Chemi-pure Blue is a good first step as I believe it has a small amount of GFO in it which targets and removes phosphates.

You could always go the dosing route to raise them. I'm currently dosing Brightwell Aquatics' NeoPhos in my 10 gallon tank as the phosphates keep bottoming out. It's fairly easy to do as long as you following the dosing directions and go slowly, retesting/remeasuring along the way.

 

[CapnWreckz]

At first glance, I would definitely think the 0 phosphates is your issue. Corals need nutrients to survive (nitrates and phosphates) so if your phosphates have been bottomed out for a while, it could lead to these issues.

As far as how to raise them, feeding more doesn't always work as you need to be feeding a food that is higher in phosphates (stuff like reef roids and some frozen foods are typically high in PO4). Removing the Chemi-pure Blue is a good first step as I believe it has a small amount of GFO in it which targets and removes phosphates.

You could always go the dosing route to raise them. I'm currently dosing Brightwell Aquatics' NeoPhos in my 10 gallon tank as the phosphates keep bottoming out. It's fairly easy to do as long as you following the dosing directions and go slowly, retesting/remeasuring along the way.

I think that's what I'm going to try out. Thank you for the advice, I'll get some NeoPhos and go slow with it.

 

[muzikalmatt]

I think that's what I'm going to try out. Thank you for the advice, I'll get some NeoPhos and go slow with it.

I'd recommend trying to raise your PO4 by 0.03 to start using the formula on the bottle. (It's a formula based on tank volume.) Then test again 12-24 hours later and see if your PO4 is where you want it to be. Then you can test again a day or two later to see how far it has dropped. Once you get a sense for how fast your tank is consuming the PO4 you can start a dosing regimen to keep it from bottoming out.