Dirty dry rock

S

Shilpan

Member
Hello!
I am aqua scaping my dry rock for my new 400L marine tank.

I've noticed a lot of dead matter on it and within the cracks like sponges and brown crust. I'm worried this will not only produce ammonia which I want for the cycle, but also foul my tank with phosphates and get me off to a bad start and algae problems early on.

Advice for getting deep in there and washing it all off? Or am I misinformed and should I leave it all there?

I was planning on letting the rocks sit in my tank with powerheads and RODI water ONLY for one week. Hoping the blasting water will remove lots of crud. Then drain the water. And then refill with saltwater then start the cycle. Do you think this is a good idea? Or will using RO water cause issues?

P.s yes I'll be adding live rock later in the cycle to help seed the tank.
 
lmforbis

lmforbis

Well-Known Member
I've always just left it on the rock. I've never started a tank with it. I usually just soak it in water for a week or so then add it. It does get really smelly. For that reason, you may want to soak it outside in a plastic bin initially for a week or two then add it to the tank to start cycling.
 
S

Shilpan

Member
Cheers! I'll definitely do an RODI washout then and soak before I cycle then.

Appreciate your advice :)
In fact maybe I'll just cure the rocks fully and let everything fall off. Can cycle with a shrimp or live rock if need be after that.

Thanks Imforbis I've learnt a lot from yourself and the others here
 
lmforbis

lmforbis

Well-Known Member
I'd cycle and cure with it in the tank since it is a new tank. just soak then change the water a couple times. Then start the cycle.
 
bang guy

bang guy

Moderator
I've encountered this type of rock before multiple times when hobbyists have wanted to save a few bucks. It often, but not always, creates an algae problem.

If it was good live rock from the start before it was dried off then it would have been loaded with not only bacteria, but small organisms that lived inside the rock. So when it was dried these organisms dried up as well and all those nutrients are still locked away inside the rock. The same thing can happen to good live rock if a hobbyist lets ammonia levels get too high.

It can take months to a year for all those nutrients to slowly leach out of the rock so it provides a steady nutrient source for algae. The good news is that there will quickly be enough filament algae to consume everything leaching out of the rock. The bad news is that the filament algae is going to grow rapidly no matter how clean you have your water since the nutrients are coming from the rock.
 
S

Shilpan

Member
Won't tap water soak mean the rocks will absorb contaminants like phosphate?

Ohh that's a shame. Oh well ill have to cure the rocks properly and then hope the nutrient export method helps keep the algae at bay.
 
S

Shilpan

Member
I read some reefers bleach their dry rock for 24hrs or soak in vinegar for 45mins, then wash it, then soak in water, add phosgard, then soak again in water.

Then finally when clean, adds them to the tank. Then starts the cycle.

Any thoughts on the usefulness of vinegar or bleach?
 
lmforbis

lmforbis

Well-Known Member
I've never had any issues with excess nutrients in the dry, dead rock once I put it in the tank,causing algae issues. Most of my rock is pukani dry rock.
As far as tap water having phosphate in it. It might, the concentration that ends up in the rock won't be higher than the concentration in the water. Tap water can have phosphate but the biggest issue is when people us it for salt water and especially top off water. The levels in the water build up causing a problem.
Some people will soak their rock in muriatic acid, HCl, to get all the crap off. Then you need to get all the acid off.
 
S

Shilpan

Member
Ah ok gotcha. So that's why after vinegar soak they was in RODI and then soak in RODI for ages.

Yeah mine is pukani. And yeah I have an RODI unit so may as well just use RODI water.
 
bang guy

bang guy

Moderator
Vinegar is fairly harmless in small doses. It's perfect for cleaning an old tank or saltwater equipment.
 
S

Shilpan

Member
OH turns out dad has some HCL, excellent

I'm soaking them in RODI water, no smell but it's only been 12 hours. Will update you guys about phosphate readings :)
 
lmforbis

lmforbis

Well-Known Member
Keep changing the water. The contaminants will move into the water until the levels equilibrate. As long as the water has a lower concentration the contaminants will continue to move that direction.
 
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