Recent content by treatmentnerd

By chance, is the pressure high? I had a problem with my oversized constant speed pump putting too much pressure on my cartridge filter and basically blowing stuff through. I had a pressure of 28 psi on a clean filter though, so my situation was fairly extreme. If your pool is similarly...

In general, you're right on. Your algae is probably dead, and you simply need to let the filter clean it out. Sand filters can often take around two weeks to complete that process. You're running below shock level for your pool though. If you haven't already done a complete shock and...

Interesting experiment. I'm curious about what kind of other results you are going to end up with. I'm glad to see it working in removing phosphate in an experiment like that. If you do end up flocking with alum, plan on letting the water settle again after the first vacuum. I've had to do it 3...

If the algae in the pool isn't putting any demand on the chlorine, you'll likely be dropping 0.5 - 1.0 ppm/day, which I believe would be around 0.5 - 1.0 cup a day of 10% bleach in your pool. (You can check me by filling out PoolMath on this site.) I would at least add that to maintain your...

Until you get the TF-100, you're largely goign to have to guess. Shock level at your CYA level is around 40 (see this chart). I'm assuming that you are up close to that at least, since you have gone from green to blue and cloudy. The major thing you need to do next is to wait for the...

Also, I believe that the alum I have at home is aluminum sulfate hydrate. I can check just to be sure, but I think that it is. Sent from my SM-G920V using Tapatalk

It likely is cost prohibitive. All of the primary chemicals discussed in the chapter can be ordered inexpensively in bulk. I'd be surprised if utilities pay more than 10% of the cost Leslie's is selling alum at. The other chemicals (lime, ferric chloride, etc.) are also cheap, though near...

I understand. If a fresh truckload is about to come anyways and you don't have present issues, simply waiting it out might be better than the money and hassle that would be involved in using alum, polyaluminum chloride or some other P remover. Sent from my SM-G920V using Tapatalk

I found these test instructions for the Taylor K-1106 test kit. It's clear that the test is for phosphate, not phosphorous, which is the unit we typically use in WW. In that case, my calculation of 9,800 ppb of phosphorous removed per 8lb bucket converts to ~ 30,000 ppb phosphate. You'll lose...

1. A 8lb bucket of dry alum should contain around 12 moles of alum at ~300 g/mol. On a pure molar basis, this would remove 12 mol of P, or 372 g P, pr 1.14 kg PO43-. A 10,000 gal pool is 37,800 liters. 372g is 372,000 mg. 372,000/37,800 = 9.8 mg/l or ppm or 9,800 ppb of phosphorous. This...

From the Water Enviroment Federation's Manual of Practice 8, (which is one of the most common references used by engineers in designing WWTPs) the chemical equation for phosphorous precipitation with alum is: Al2(SO4)3*(14 H2O) + 2 H2PO4- + 4 HCO3 ---> 2 AlPO4 + 4 CO2 + 3 SO42- + 18 H2O Note...

I need to review the math above for equivalence, but I know that in WW we expect to need about 3 lb Aluminum for every pound of phosphorous. This is approximately double what the pure chemistry would suggest, similar to what JoyfulNoise said above. I'm not sure what you cost numbers are from...

I doubt that an occasional use of alum would ever generate concerning sulfate levels (~300 mg/l from here 3 – Sulphate attack | ) like sodium bisulfate use would, but extremely frequent dosing certainly could. You could also acheive the same results with polyaluminum chloride floc without the...

Floc could also help speed up the process of the pool clearing up, but it shouldn't be added until the pool goes from green to blue and cloudy. It's not normally recommended because it can be tough to deal with, but it does work if used for the right purpose (clearing cloudy water.) It doesn't...

Okay, so I want to dive in here. I have not read all of the 300 posts in the thread so far, but I believe I take a different approach to this than most. Professionally, I'm an engineer and I design water and wastewater treatment facilities. Many wastewater treatment plants have to hit low...