Does dry rock leak phosphate and feed GHA?

Jose_Padilla · Feb 21, 2021

I was recently watching a video by Tidal Gardens about the "Ugly Phase" and it was mentioned that dry rock most likely leaks nutrients into the water to feed GHA and other algae outbreaks. If this is the case, will cycling my tank with both dry and live rock help avoid the ugly phase, or is it best to use live rock to limit the chances and/or duration of the ugly phase?

I like the aquascape possibilities using dry rock, but it is imperative that I avoid as much of, and have as short an ugly phase as possible, so I can keep my wife happy.

waqas_01 · Feb 21, 2021

If you've already bought the dry rock and have some space, run a brute container with saltwater and dose lanthanum chloride until they don't leach phosphates anymore. Without livestock you can dose directly into the container and not worry about anything dying. You will have to do water changes on it though to prevent the precipitate from clinging to the rocks or dose into a 5um filter sock.

For me I started with dry rock that I had bleached but also had a turf scrubber so any algae that wanted to grow was in the sump area. I maybe had a week or two of a slight ugly phase.

Dry rock is cheaper but requires a little more time to establish itself.

Jose_Padilla · Feb 21, 2021

waqas_01 said:
If you've already bought the dry rock and have some space, run a brute container with saltwater and dose lanthanum chloride until they don't leach phosphates anymore. Without livestock you can dose directly into the container and not worry about anything dying. You will have to do water changes on it though to prevent the precipitate from clinging to the rocks or dose into a 5um filter sock.

For me I started with dry rock that I had bleached but also had a turf scrubber so any algae that wanted to grow was in the sump area. I maybe had a week or two of a slight ugly phase.

Dry rock is cheaper but requires a little more time to establish itself.

Space constraints aren't going to make that feasible for me. Guess I'm just going to have to do the best I can do with Live rock.

waqas_01 · Feb 21, 2021

I may have overwhelmed you with my response. Dry rock isn't a guaranteed phosphate leach but if you see that it is leaching take some precautions.

Start off with a refugium in place so anything in the tank has to compete with the refugium. Go light on the feedings and base them on livestock. Have a good clean up crew - not necessarily hundreds of crabs and snails.

As a beginner you're probably best to start with liverock just because it'll kick start your bacteria populations. Start with a smaller volume tank where you can do a bit of a larger water change in case things get out of hand and actually make a dent in the water chemistry.

Enjoy the process! Good luck.

RocketEngineer · Feb 22, 2021

Early on, keep lighting to a minimum. I don’t plan to turn on tank lights for quite some time so the bacteria have access to the nutrients vs algae which needs light. You may not be able to keep it off all the time but the lower the lighting the lower the algae levels. Good luck.

Screwgunner · Mar 7, 2021

If it is dead rock from ocean blue then yes it might have phosphates if it is old aquarium rock you had better believe it. But the dry rock that is made no I don't think so . The problem is at the end of the cycle all the ammonia and nitrite is turned in to nitrate plant fertilizer. A good skimmer will keep that down . Algea scubber good refugium good. Any plant you can grow out side the DT is a big help.