Recent content by max2k

depends where your FC will be at that moment. You can use PoolMath link at the top to estimate how much. As an example I entered 20K for pool volume and it says 1 gal of 8.25% bleach will bring FC up by about 4.5 ppm.

I have couple questions: - what did you use to measure FC with 3 significant digits? - how do you chlorinate your water?

73% calcium hypochlorite? I would use plain bleach instead- your CH is already high at 300 and you said drain is not an option. For your pool volume (20k?) that 20 oz addition raised your FC by 5 ppm to 8 ppm which is still below even maintenance level recommended above let alone SLAM.

Re: underwater lightbulb keeps burning out IMO, this is most probable cause- use of a bulb not rated to be installed in the pool light.

OK, looks like normal algae reaction so far. Please forget about FC loss test for now and continue SLAMming: add 2 gal of bleach, leave pump running and brush whenever you can.

are you using K2006/TF100 test kit? It would be too much of FC drop even for algae. So this would be either measurement error or some other chemicals added there in the last year besides chlorine.

I believe after 3 gal of bleach went in they're around 21 atm.

that is new to me- looks like they do regeneration at their location or it is one of the 'filter' systems altogether. Please find out details how it works to be sure what kind of chemicals would go into your pool at the end. Pool presents unique challenge as it tends to concentrate contaminants...

have you got a chance to calibrate it? Like buying known concentration solution(s) and see what it shows? When some meter shows some numbers they're just that- some numbers unless it comes with very solid spec and produces consistent results on standard solutions. That usually comes with...

you do realize it was 20 extra drops for 1 additional FC reading? The pic of the pool is taken kind of in dark conditions and FC loss was surprisingly low. I don't know about you but something is off- the pool with such color should've lost almost all FC overnight.Since the SLAM already started...

offtopic but since OP is asking: real softeners work on the idea of replacing Ca ions with Na ions in ion- exchanging cylindrical tanks filled with special polymer granules. As you can see there's no scavenging of the salt, quite the opposite: hard water gets replaced with salt one. Since the...

it is- pics ^^^ in post #22

So is this correct: last night FC=8.4 ppm (25mL), this morning FC=8.5 ppm (10mL) and no chlorine additions in between? If so- do you have SWG / chlorine tabs dispenser / any other chlorine source in the pool? I'm not so worried about 0.1 ppm 'increase' as the test is not that accurate to begin...

Re: underwater lightbulb keeps burning out these are very different beasts compared to normal incandescent light bulbs- they work in very overloaded mode 'assuming' the water is always present around its enclosure. It will simply burn out if you turn it on outside of water.

I believe lowering pH is one of the recommendations prior to SLAM, it makes the process more efficient. The fact you won't be able to monitor it doesn't change much- it will still be there at the end. FC is the only parameter which is actively changing during SLAM. You got accurate values of pH...