Coral Regression - Need Opinions

[Copperband86]

So let me give you guys a little background on my tank 1st. It's been running and cycled since March.
75gal DT with a 30gal sump.
Reef Octopus skimmer, media reactor, live rock as filtration.
Lighting is a Current Orbit 48" LED fixture.

Current livestock is a pair of Domino Clowns, 1 Foxface, and 1 Coral Beauty Angel.

Tank parameters: Nitrate 0-5ppm, Nitrite/Ammonia:0ppm, Ph 8.0, Calcium 380-400.

I use only RO water for water changes and Reef Crystal salt. I dose with calcium and a reef buffer. Otherwise, that's it.

My issue seems to be with corals that I have never had in prior tanks. Right now I have some ricordia (doing great), Hammer (doing terrible), a couple Acan frags (1 great, 1 bleaching) and just picked 2 colonies of red and yellow Zoas.

My tank parameters are spot on, although I admit my calcium was sitting around 280-300 during summer (not dosing as much) but I've gotten it up to 380-400 range so far. The Ph could be higher, but 8.0 should be acceptable. I'm using a buffer to try and raise it. Maybe it's the fact my calcium was low, but the hammer just keeps receeding and probably will be a goner within a couple weeks. Tank placement is on the sand in low to medium flow and has been in the tank for almost 2 months. Acans are on the sand as well, although one is bleaching like crazy while the other looks pretty good and no bleaching.

I could just be stressing about these, but they should be low maintenance corals and survive these conditions. I'm a bit perplexed as to why this is happening. Could just be rotten luck, could be the low calcium for a couple months, but I'm beginning to question if something else is off. Any suggestions on this?

[mcgyvr]

First.. stop the PH buffer.. Don't chase PH and 8 is just fine anyways.. Instead focus on keeping alk stable..

Second.. I fail to see how you need to dose anything in a 75G tank with only a few soft corals and some LPS.. But if you have a lot of coralline algae I suppose it could be consuming quite a bit. Are you never doing water changes?
Have you calculated your daily consumption of cal/alk/mag?

Corals need stability.. you have already admitted to letting levels swing which is not good..

Really no point in measuring ammonia/nitrite anymore..
alk/calk/mag/salinity/nitrate/phosphate are what you should be focusing on for the most part now..

Sometimes all it might take is moving a coral to a better area.. They might not like the light or the water flow or whatever too..

And lastly.. In general that light basically SUCKS for anything but low light corals in shallow tanks.. It just doesn't have the power to penetrate down deeper with any decent level of light.. It could be the reason you are having problems but pictures are far better than "doing terrible" whatever that means..

[Copperband86]

Originally Posted by mcgyvr

First.. stop the PH buffer.. Don't chase PH and 8 is just fine anyways.. Instead focus on keeping alk stable..

Second.. I fail to see how you need to dose anything in a 75G tank with only a few soft corals and some LPS.. But if you have a lot of coralline algae I suppose it could be consuming quite a bit. Are you never doing water changes?
Have you calculated your daily consumption of cal/alk/mag?

Corals need stability.. you have already admitted to letting levels swing which is not good..

Really no point in measuring ammonia/nitrite anymore..
alk/calk/mag/salinity/nitrate/phosphate are what you should be focusing on for the most part now..

Sometimes all it might take is moving a coral to a better area.. They might not like the light or the water flow or whatever too..

And lastly.. In general that light basically SUCKS for anything but low light corals in shallow tanks.. It just doesn't have the power to penetrate down deeper with any decent level of light.. It could be the reason you are having problems but pictures are far better than "doing terrible" whatever that means..

The reason I started dosing was because the calcium was at 280. I initially started out as a FOWLR, but that only lasted about 3 months before I decided I missed having corals. I also was using Instant Ocean, switched to Reef Crystals recently. As for water changes, I'm religious with 20% weekly. I should have realized I had low calcium when I had no coraline algae growing after 6 months, but frankly I was preoccupied over the warm summer months with my cottage. Coral-wise, I'm really only going to be doing softies/LPS. Never really liked SPS, so after reading up I figured why make a massive investment in lighting when a simple fixture could probably do the job. About a decade ago I used some T5's on my tank and the corals loved it. With the concentrated light from LED's I assumed they would be on par if not superior to that setup.

[JWClark]

What is your alk? This is likely part of the problem. Reef crystals already has alk levels above the limit that I am comfortable with, then adding the pH buffer probably added even more, causing all your Ca to precipitate out.

It's cheaper to stick with instant ocean and then add some Mg and Ca as needed. My experience is that plain IO is more consistent and the alk is around 10dkH instead of 12. Just add a little CaCl and Mg solution and it is better than reef crystals. IMO.

Also, every water change you need to measure the alk, Ca, and Mg of the new water and add supplements to raise, if needed, to ensure your new water has the same parameters each time. If doing 20% water changes at one time then make sure these parameter match your tank water.

Suspect what has been happening is you do a water change, alk spikes, then you use pH buffer and alk crashes (as alk and Ca precipitate out), then water change and alk spikes, and on and on. You get white dust on powerheads and such?

If pH is a concern then use a CO2 scrubber on your skimmer. Other than that, ignore pH.

[Copperband86]

Originally Posted by JWClark

What is your alk? This is likely part of the problem. Reef crystals already has alk levels above the limit that I am comfortable with, then adding the pH buffer probably added even more, causing all your Ca to precipitate out.

It's cheaper to stick with instant ocean and then add some Mg and Ca as needed. My experience is that plain IO is more consistent and the alk is around 10dkH instead of 12. Just add a little CaCl and Mg solution and it is better than reef crystals. IMO.

Also, every water change you need to measure the alk, Ca, and Mg of the new water and add supplements to raise, if needed, to ensure your new water has the same parameters each time. If doing 20% water changes at one time then make sure these parameter match your tank water.

Suspect what has been happening is you do a water change, alk spikes, then you use pH buffer and alk crashes (as alk and Ca precipitate out), then water change and alk spikes, and on and on. You get white dust on powerheads and such?

If pH is a concern then use a CO2 scrubber on your skimmer. Other than that, ignore pH.

I need to start measuring alkalinity, as I truly don't know what it is TBH.

No, no white dust on PH's or anything.

[mcgyvr]

Corals like many humans hate change.. Sounds like you've been making some..

But if you plan to stick with 20% weekly changes I would switch back to regular IO salt vs RC.. Then get and keep your parameters stable and hopefully everything will do good from there on..

[Copperband86]

Originally Posted by mcgyvr

Corals like many humans hate change.. Sounds like you've been making some..

But if you plan to stick with 20% weekly changes I would switch back to regular IO salt vs RC.. Then get and keep your parameters stable and hopefully everything will do good from there on..

Thanks for the suggestions guys. You have me seriously contemplating my lighting setup, salt, and dosing. I'll knock off the buffer and continue to work on getting the parameters as stable as possible.