Regenerating GFO

I'm changing mine at 2 weeks instead of 3 as I did with totally new. I am also alternating new with regenerated to try and notice any differences in the tank while using the regenerated. Keeping batches separated 1st regenerated and 2nd, I havn't got to a third cycle yet.
 
thi7b said:
Where can I find Sodium Hydroxide. Pool shop by my house does not carry them.
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Lowes sells them as Roebic Crystal Drain Opener in the Plumbing section

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dja1980 I guess it is a little of both I dont feel the regenerated will ever be 100% recharged and because it is a lot cheaper I can afford too. I am waiting on my new Hanna Phosphate checker to come in. I am hoping this will give me a little more confidence in the process.
 
Well I say this is a great thread I am shocked it has not taken off more. Okay for what I did was I did not use the vinger soak at all, but I used a lye crystal cleaner from our home hardware. The msds sheet states the only Sodium Hydroxide 95 "“100%. To regenerate 4 cups of GFO I usd 20 teaspoons and 2 gallons of water, I believe this would be in line with this thread. I let it sit for 48 hours and then really rinsed it off well and this worked. I know that the gfo was exhausted and it was regenerated by what it was pulling out of the water. Now I would like some feed back, is what I did in line. I was feeling I really didn't need to leave it 48 hours, I did stir it in the morning and night.
Also though I my phos in my tank went down, but after putting my regenerated gfo I believe my nitrates when up. Does this make sense.
Thanks
 
tatuvaaj said:
I stop @ ~10, getting it to that is enough work :lmao:
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If you've washed out most of the hydroxide with RO/DI, you'll find by simply adding a few drops of muriatic acid (HCl), the pH will drop quite a bit. The very small amount of hydroxide retained after copious RO/DI rinsing is still enough to register around 10 on pH. You can either add a few drops of acid and check the pH, or you can use it straight in your system as is as long as you're confident that the bulk of the hydroxide is rinsed out. My extent of rinsing is more a function of the amount of GFO fines (orange/brown-colored rinse water); I keep rinsing until the rinsate has an acceptably light color. It seems my GFO is breaking down over time, since I'm on my 6th or 7th reuse and I don't recall seeing as much breakdown during the first regeneration cycles. I wish I'd measured the total volume I began with to see if there is a volumetric reduction. Also I've regen'd with and without an initial acid rinse and don't see a performance difference in the resulting product (could be that the GFO mechanically breaks down, taking calcium carbonate, if any, with it). Also, I use the regular capacity GFO, and will be trying the high capacity in the near future. Perhaps the high capacity is harder, and thus less prone to breakdown.
 
badonkadonk yes on the breakdown I do about the same thing wait until the rust colored water or fines are greatly reduced. I use the high capacity and can see a small reduction in particle size and I'm only on my third regeneration.
 
I have about 700ml of spent RowaPhos that I want to regenerate. I first soaked them in about 1.5% muriatic acid for about 4 hours. I tested the unadjusted (PH) solution during the first hour and at the 4th hour, zero phosphate detected from my API kit. There was quite a bit of bubbles generated during the first two hours. I guess from the CaCO3 deposited on the surfaces of GFO granules.

I then soaked the spent GFO in 2 liters of 1M NaOH. The water turned to milky orange immediately. I tested the solution immediately in 10x dilution, unadjusted for PH, with the API kit and it reads 5ppm which means the original solution has a concentration of 50ppm. I will test it again in 2 hours.
 
I did another test 2 hrs later. This time I double diluted the solution (5ml added to 95ml of RODI water. Then take 5ml from the diluted solution and added to another 95ml of RODI water). So the final dilution is 400X less than the original concentration. Using my Hanna Phosphate Checker, I got 0.18ppm. if my calculation is correct the phosphate level in the original and unadjusted solution was about 72ppm 2 hrs after soaking. I wonder if more phosphate will be released from the GFO the longer they soak in the NAOH solution.
 
There is definately a loss of grain size on the GFO. We accidentally left some in the lye solution for 3 weeks. A lot of it now looks like black dust. OOPs
 
I've read through most of the post. I am in no way close to a chemist or understand chemistry very well. But in order to regenerate GFO. All I have to do is use 40grams of NaOH to 1 liter of ro/di water times 5? of the amount of GFO i want to regenerate and let it soak for 24hrs? Then after that, rinse the GFO till the water runs clear. Did I get it right or am I leaving out a step? I'm currently using BRS HC GFO and this stuff is expensive. Changing it out every 2 months but if I can regenerate. I would change it out more often to reduce the algae already in my tank. Please advise weather I got the steps correctly for regenerating.

Thanks,
Mike
 
In my earlier post in May, I recharged my BRS GFO pellets first with 3% muriatic acid as a presoak solution for 24 hours and then in 1M (40gm NaOH in 1L of water) x 48 hours. When I started to rinse the GFO, most of them turned into orange mud and I ended up with less than half the initial volume of GFO. I have not used that batch of recharged GFO as it is too soft to use.

2 weeks ago, I recharged about 1 lb of BRS HC GFO. This time I skipped the acid presoak and went straight to NaOH but I only used 0.5M (20gm in 1L) x 4 days. This time the result is much better and I ended with most of the original volume. I believe the harder HC GFO is more suited for regeneration than the softer granular or pelletized GFO. The PO4 level of the solution after 24 hours was >10ppm. After 4 days and with five rinses with RODI water, the solution was 0ppm per my Hanna Phosphate Checker. I will be using this batch when my current GFO exhausted.
 
Simon, Thanks for the info. I am almost due to change my GFO out at my next W/C. I will save that used batch of GFO and try to regenerate it using .5M
 
i see...couldn't find the one in your link at Home Depot. anyways. I needed to clear up some drains in my house lol. Guess i'll go look for that at lowes
 
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