NaOH treatment

[choff]

Hi Randy, I recently read on glennfs DSR thread about a technique he used to combat bubble algae. He mixed a 10% NaOH solution and spot treated the algae. He turned off all the pumps and let the lye solution stay on the algae for I think 30 sec and then turned the pumps back on.

I have never heard of anyone doing this before. Do you see any potential hazards with this chemical in our reef?

I'm considering this technique in an attempt to eliminate a patch of lobophora algae.

Thoughts?

Thanks for your time!
Mike

 

[Randy Holmes-Farley]

It will boost pH and alkalinity substantially. It will kill anything it lands on in high concentration.

But it may be a useful local treatment. People use a similar material (calcium hydroxide) to kill aiptasia.

 

[choff]

Thanks Randy. This is near last resort option.

 

[Randy Holmes-Farley]

Ok, be sure to watch the alk, and pH if you can.

 

[pfoxgrover]

I've been using this to treat hair algae since GlennF recommended it to me. It works well but you have to be very careful not to get it on the corals, if you do you can dust them off but might get some burned spots.
I made an applicator out of a rigid air line tube with a 10 ml syringe on one end and that works well for getting the NaOH on the algae but not on the corals.

I mix 11 grams in 100ml of water for a 10% solution. Skin and eye protection is a good idea and be extremely careful not to get it on anyone or let children anywhere near it.

 

[biom]

Ive been using mix of NaOH and Ca(OH)2 to form paste like substance to fight aiptasia, it works well but it is very dangerous for your corals. I think the best way (yes it's pretty long way) to fight hair algae is keeping nitrates and phosphates low and wait until your system reach equilibrium, everything else will have temporary effect.

 

[pfoxgrover]

I agree this is not a long term solution but once hair algae gets a foothold, lowing phosphate and nitrate doesn't seem to kill it in my experience.

 

[Randy Holmes-Farley]

I agree this is not a long term solution but once hair algae gets a foothold, lowing phosphate and nitrate doesn't seem to kill it in my experience.

Perhaps you didn't lower it adequately. Usually it works for green hair algae. :)

 

[pfoxgrover]

Perhaps you didn't lower it adequately. Usually it works for green hair algae. :)

That is possible. My tank is 240 gallons. I am very frustrated with PO4 test kits and haven't been testing for it. If my level was 0.08 PO4 and I wanted to lower the value low enough to kill hair algae, how much GFO do you think that would take?
Thanks,
Paul

 

[pfoxgrover]

I broke out the test kit and according to my hanna P tester the level is somewhere between 0.08 and 0.03 PO4. I tested it several times and came up with an average of 0.05 PO4.
Nitrate tested zero per red sea kit.
I ran 2 cups of gfo for one week and replaced it yesterday with two cups of PHOS FX. I would expect the levels to be about as low as I can get them but I guess not? I have very low confidence in PO4 test kits at these low levels.

Maybe I'm underestimating the amount of media I need. If my level was 0.08 PO4 and I wanted to lower the value low enough to kill hair algae, how many cups of GFO do you think that would take for 240 gallons?
Thanks!
Paul

 

[Randy Holmes-Farley]

I couldn't say with any certainty because there may be as much or more bound to rock and sand as in the water.

 

[pfoxgrover]

About a year ago I replaced the entire sand bed and i removed about half of the live rock. I have some pretty old rock that was exposed to high phosphate long term but I have been using phosphate remover regularly for about 3 years so I hope there isn't much bound to the rock. If I knew how much it might be contributing I would consider replacing the rock. Here is a pic

 

[biom]

Very nice tank. IME the best way to reduce phosphates (and all organics) bonded to live rock is liquid carbon dosing vodka/vinegar. GFO will bind phosphates from water column only.

 

[Randy Holmes-Farley]

Even if the rock is pristine, once in water at 0.08 ppm phosphate, a substantial amount will bind and make lowering the levels more difficult in the future. It is not a big problem, just a factor that must be accounted for in trying to determine how long it will take, or how much GFO it will take, to reduce phosphate. :)

 

[pfoxgrover]

Very nice tank. IME the best way to reduce phosphates (and all organics) bonded to live rock is liquid carbon dosing vodka/vinegar. GFO will bind phosphates from water column only.

Thanks. I am going to switch from biopellets to liquid carbon dosing to better control the levels.

Even if the rock is pristine, once in water at 0.08 ppm phosphate, a substantial amount will bind and make lowering the levels more difficult in the future. It is not a big problem, just a factor that must be accounted for in trying to determine how long it will take, or how much GFO it will take, to reduce phosphate. :)

Thanks Randy! I guess that explains why I can't kill the GHA with GFO. Some of my live rock may be close to 20 years old. I wonder if all the gfo in the world would help me now.

 

[Randy Holmes-Farley]

Using enough GFO should do the trick. :)