Coral's won't open

[blue raptor]

Hello,

I've had my 75g for 6 months and for the last 2-3 days some of my pieces won't open. Nothing has changed in my routine. Pieces affected are mainly Zoa's, Green Start Polyps, some of my hammers and acan. My wellsophyllia and frogspawn seem fine. Fish are acting normal and eating as usual. My last water change was Saturday (bi weekly of 20 gallons)

Salinity 1.024
dKH 7
P04 .05
Nitrate 0
Temp 75

 

[mandy111]

Its really important to know what you other tests are when it comes to corals.
Mag & cal play a fairly important role in healthy corals also.
Can you test these two ?
Has the flow changed in the tank at all ?
With 0 nitrates you may also need to be feeding some corals. Most LPS like a little nitrate and phos. If your running a low nutrient system then feedings may be needed.

 

[bang guy]

When corals suddenly look worse my first though it always a change in Alkalinity, either too low or too high.

* - edit - OK I see that your Alkalinity is very low. Might want to fix that. Don't try to fix it in a single day though, raise it gradually.

 

[blue raptor]

Not sure what caused the swing, will do small dosages in the next week. My calcium was at 400, and as far as mag, i will be going to my LFS, they check Mah using the Hanna Tester.

Flow hasn't changed at all.

 

[mandy111]

When corals suddenly look worse my first though it always a change in Alkalinity, either too low or too high.

* - edit - OK I see that your Alkalinity is very low. Might want to fix that. Don't try to fix it in a single day though, raise it gradually.

Its very interesting you say alk is very low ?
We use natural sea water here and it is delivered at 6 dkh, I personally like to run 8 so I raise mine, but hundreds of reefers here with very nice systems (including sps) run theirs at the delivered number of 6.
Is it not more important that if he wants to run 7 it is consistently at 7 rather than chasing numbers ?
I have seen and know of many highly succsessful reefers that run 7 or below ?

 

[bang guy]

The problem with a 6dKH or 7dKH Alkalinity level in a small reef is that it can drop below 5dKH in just a few days. In a reef of rapid growing corals it could even take less than a day. 5dKH is the start of where corals cannot build skeleton. If you can maintain 6dKH that's great but without a reactor or a limewater drip system I think it's dangerous (for a reef system).

 

[mandy111]

The problem with a 6dKH or 7dKH Alkalinity level in a small reef is that it can drop below 5dKH in just a few days. In a reef of rapid growing corals it could even take less than a day. 5dKH is the start of where corals cannot build skeleton. If you can maintain 6dKH that's great but without a reactor or a limewater drip system I think it's dangerous (for a reef system).

thats is why I actually bring mine back to the 8 mark every time, i consider it a safety net lol.
But I don't think 7 would be affecting the corals, as I said many people run the nsw here at 6 - 7 and have amazing corals.
I really like having that buffer in case my doser fails.

 

[bang guy]

thats is why I actually bring mine back to the 8 mark every time, i consider it a safety net lol.
But I don't think 7 would be affecting the corals, as I said many people run the nsw here at 6 - 7 and have amazing corals.
I really like having that buffer in case my doser fails.

I could definitely be wrong in the interpretation of my personal experiences. That is the problem with anecdotal evidence. It's also the beauty of a variety of experiences.