white water mold

[eaglehawk]

i have a pool that is covered a large percentage of the time and i am constantly battlling the dreaded bacteria. i brush daily along with slamming and algaecide 60. the water has a slightly turbid appearance i cannot seem to get rid of this year. i also have added well water through a filter and have had some staining. i have added a metal chelator which helps but i suspect the iron level is causing the faint brownish tint. the ph is holding in the 7.2 to 7.6 range. my cya is down to 30 to 40. the alkalinity is down to 90.my free cl is holding around 1 to 2,but my total is 3 to 4. i used to use cl tablets and non cl shock almost exclusively until my cya got to 120 to 150 or higher so i been adding liquid bleach and shut the chlorinator down. it is a vinyl pool which is winterized each year. i have used some organic products such as pool perfect and seakleer for water clarity and phosphate removal that have worked in the past but now i cant seem to eliminate the faint haze. my filter sand is original 2007. should i change sand? i have an oversized filter which does not register much pressure change but seems to remove the whiter turbidity which i see in the sight glass when i backwash but not as much as in the past. should i try adding a filter aid? i have used a filter cleaner recently when backwashing which helped last season but not this year. i have brushed daily especially in dark areas and kept the white slime in those areas as well as brushing all surfaces. i use the pentair 78dpd+ test kit.

 

[chem geek]

Welcome to TFP!

What you need to do is described in more detail in the Pool School.

First and foremost, get a proper test kit. You need a FAS-DPD test kit to measure more accurately and to be able to measure high chlorine levels during a SLAM. So get the TFTestkits TF-100 or the Taylor K-2006 (see Test Kits Compared.

Next, you need to SLAM - Shock Level And Maintain shocking your pool. This will kill off the white water mold though if that is what you have then you will need to get behind light niches (if you have them) and under removable ladders.

For improved filtration you can Add DE to a Sand Filter.

Also note that the minimum FC level for your CYA level is described in the Chlorine / CYA Chart. Even if your CYA is down to 30-40 ppm (which if these are pool store numbers are highly suspect) then the minimum FC is around 3 ppm so you should not get as low as 1-2.

 

[eaglehawk]

the cya numbers are from my test kit and i have ordered the recomended test kit along with slamming with bleach and a proprietary product called pink cure which is a cationic polymer that i used last year to remove dead organic matter. it is looking better. i will keep you posted. i have also studied your posting about cya and free cl which certainly applies in my case. i just have a year of basic college chemistry but i was an industrial chemist in electroplating for thirty years. your posting is a little advanced for me but the methodolgy makes a lot of sense. true analysis always involves dealing with background interference and reaction. thanks for your reply.