Re-starting tank...does my dry rock have phosphates?

[LilElroyJetson]

I’m going to be re-starting my tank and setting things up from scratch after having had everything in storage for a few months after a move.

Before moving, I dried my live rock outside for about a month during the summer to kill off some unwanted aiptasia and algae before storing it for future use. It’s been sitting dry ever since. The water quality in my tank at the time of tear down was poor.

Is there a way to know whether my live rock has phosphates that will be released when I set up the tank again? My plan was to set up my dry rock with live sand and cycle for 6 weeks or so. I’d appreciate any insight.

 

[Randy Holmes-Farley Verified Community Expert]

Did it come from water with elevated phosphate?

 

[LilElroyJetson]

I couldn’t recall the reading but it’s safe to say most likely. Was wondering how much drying would kill the phosphate off, if any, and what the best way to approach would be? Do I just cycle longer to allow for the die off/release of phosphates?

 

[mtfish]

All I can think of is to put some in a container with saltwater, take an initial PO4 reading. Circulate the water with a small powerhead. Wait like a week and see if the PO4 number goes up. If so, treat all the rock with lanthium chloride aka seaklear until levels go to zero. Good luck and welcome back to the adventure!

 

[LilElroyJetson]

All I can think of is to put some in a container with saltwater, take an initial PO4 reading. Circulate the water with a small powerhead. Wait like a week and see if the PO4 number goes up. If so, treat all the rock with lanthium chloride aka seaklear until levels go to zero. Good luck and welcome back to the adventure!

Thanks mtfish. Wondering if it’s easier and safer to just pick up some cured dry rock from my LFS at this point and call it a day.

 

[mtfish]

Thanks mtfish. Wondering if it’s easier and safer to just pick up some cured dry rock from my LFS at this point and call it a day.

Depends on how much rock you are talking about and how much you like the old rock. Is it really good, porous rock? Nice shapes? Easy to stack or scape? It is not really hard to deplete PO4, but does take a little effort and time. But... time is money, so if you can get other rock similar, then could go either way. Of course, I am cheap, so I would go the treatment way.

 

[LilElroyJetson]

Depends on how much rock you are talking about and how much you like the old rock. Is it really good, porous rock? Nice shapes? Easy to stack or scape? It is not really hard to deplete PO4, but does take a little effort and time. But... time is money, so if you can get other rock similar, then could go either way. Of course, I am cheap, so I would go the treatment way.

Yeah my rock is really good rock but the time saved sounds more appealing to me despite having to cough up the extra cash for safe rock.

How bad of an idea would it be to just set up the rock in the display tank and cycle and lower phosphate as needed in the display tank itself before moving forward with the tank? I’m in an apartment so space is limited to treat rock in external tubs as well as other considerations such as noise, mess, etc.

 

[mtfish]

You can definitely do this in the DT, but I would still use Seaklear. I have to lower PO4 in my DT and I use a 5 micron filter sock. I mix 10 ml of Seaklear in one gallon of water and drip this into the sock at about one drip per second. I have a small pump that I pump water into the sock. Works very well for me to keep PO4 in check. If you do go the Seaklear route, be sure to get the "commercial strength". I buy it online. You can do this while cycling the tank or even after you start stocking. I have been told that the precipitate can be harmful to fish so it is best to filter.

 

[LilElroyJetson]

You can definitely do this in the DT, but I would still use Seaklear. I have to lower PO4 in my DT and I use a 5 micron filter sock. I mix 10 ml of Seaklear in one gallon of water and drip this into the sock at about one drip per second. I have a small pump that I pump water into the sock. Works very well for me to keep PO4 in check. If you do go the Seaklear route, be sure to get the "commercial strength". I buy it online. You can do this while cycling the tank or even after you start stocking. I have been told that the precipitate can be harmful to fish so it is best to filter.

Great to know. Thanks for this info. Just to be clear, if I put the dry rock into my DT, add live sand and maybe a piece or two of live rock, and test for phosphate, as long as the levels are within reason, is it probably best to just treat with chemi-pure and chaeto in the sump until the numbers are optimal? Or would you still advise going the Seaklear route?