Thoughts on water quality??

[Wildman]

I've had my tank up and running for over 6months. It was also started using sand and rock from previous tank. My paramaters are pretty consistent and what seems to be excellent. Nitrates, nitrites, phosphate all undetectable. Ph says between 7.8-8. DKH stays between 9-10. Calcium stays right at 400. Mag has been good every time I have checked it. Around 1200-1300 maybe(can't remember right off but it doesn't change).

What i have noticed is around the 2 week mark after a water change my LPS and some zoas seem to not open as fully. SPS still look great with good polyp extension and coloring up nicely. It can even be a small 10gal water change on about 90gal system and everything looks great for about 2 weeks. A large water change makes no difference in the time period. I am beginning to wonder if I am using something up instead of a buildup of something bad in that time frame. None of the parameters above change after the water change.

Any thoughts??

 

[Rob.D]

It might not be water quality as much as lighting might have something to do with it.

 

[Wildman]

What are you thinking lighting wise? They are on a timer and always the same.

 

[mike007]

What test kits are you using? Are you dosing anything?

 

[glb]

Have you ever tested at the two week mark and then right after a water change? It would be interesting to compare the numbers.

 

[Rob.D]

What are you thinking lighting wise? They are on a timer and always the same.

It's a shot in the dark that the corals could simply be reacting to the lighting. I have a couple of LPS corals that were reacting in a similar fashion, they were directly under LED's and I moved them to the edge of the tank, after moving them they no longer close up.

Also have you checked for stray voltage?

 

[Wildman]

What test kits are you using? Are you dosing anything?

I use a variety of kits to cross reference and have also taken a sample in to get tested.
I don't dose anything yet because I have a very small bioload. 5 very small fish and a cleanup crew.

Have you ever tested at the two week mark and then right after a water change? It would be interesting to compare the numbers.

I have and get the exact same results.

 

[Wildman]

Rob, I have had issues acclimating coral to the LEDs and have had to shade several but this is different. They will open and look great for close to two weeks after a water change and then will start to not puff up as much. I will do a WC at a little over two weeks and they will open up and look great again. This has been consistent for over two months.

I am not strictly opposed to bimonthly WC. Just wanting to figure out the correlation.

 

[Esage]

Rob, I have had issues acclimating coral to the LEDs and have had to shade several but this is different. They will open and look great for close to two weeks after a water change and then will start to not puff up as much. I will do a WC at a little over two weeks and they will open up and look great again. This has been consistent for over two months.

I am not strictly opposed to bimonthly WC. Just wanting to figure out the correlation.

I wish I had an answer to this. I had similar issues when I was running a 34 gallon cube. I could always tell when it was time to do a water change by the way my corals looked. After I would do a change all corals looked great for two weeks and than they would start to close up, do a water change and everything looked great. I could never figure it out so I started doing smaller weekly water changes.

 

[J062682l]

I had the same problem in my 55. A water change a week does the job.

 

[Spongie]

I would try testing before and after wc just to satisfy curiosity (yours and ours). But I kinda agree with Esage about smaller more frequent water changes. I would try and do 5g a week and see if everything stabilizes for you. But testing before and after will probably help you get to the bottom of the issue faster.

Edit: re-reading I see that you said that you have tried testing before and after, so...scratch that.

 

[Wildman]

I believe I have found at least part of my problem. I hooked up my Reefkeeper a week or so ago and my PH has crept to 8.7. I have not calibrated it in a while so I need to verify but I believe it is close. Testing with my other test kit it is possible for it to be close to this high as it is not as precise.
I added 1/4 cup of vinegar to keep with the recommended 1ml per gal and it came down to 8.5 but for only a few hrs. It is now back to 8.7. Any suggestions on getting it down? I have CO2 for planted aquariums I could use. I am also going to do some more testing on makeup water and RODI water.

 

[Wildman]

Been reading some more. I don't think adding CO2 is going to help much due to my skimmer off gassing the CO2 I would add(also probaly why the water doesn't have enough CO2 presently).
What about HCL? Says it will lower PH as well as DKH. This would be ok as all my levels are really high. I am not adding any additives but the biweekly WCs with Reef Crystals are pushing levels up. Not enough coral to deplete anything yet.

 

[Wildman]

Looks like the probe was the problem not PH. I didn't know the probe would creep like that over a few weeks. So back to the original question of what levels change over a couple weeks.