having possible mustard algae problem 3 weeks now

[bluebayou]

I appreciate your continued help.

The Kem Tek is no longer available from Amazon. I see from the MSDS that the Kem Tek one is 7% lanthanum chloride. The Orenda PR-10000 lists 'proprietary" chemical composition. PHOSfree by Natural Chemistry lists 7-13% lanthanum chloride. Have you heard anything about that one?

It occurred to me that the town switched to a communal well earlier last year. Previously, we were receiving water from a nearby industrial mill. Not that I am assigning blame, but that would explain why we never had an algae problem until last summer.

[PoolDoc]

I just confirmed that Amazon problem. I'm not sure what's going on. I'll check tomorrow with Amazon and Kem-Tek, and see if I can get an answer.

You might check your local Home Depot; some of the carry Kem-Tek products. Mine does not.

[bluebayou]

I am back home. I purchased Phosfree from Natural Chemistry and I purchased the Aqua Chek test kit that you listed. The Phosfree came with a test kit included.

I tested the phosphate level with the both. The Natural Chemistry one shows over 1000 ppm for phosphates. The Aqua Chek one shows at least 300 ppm, maybe a little darker.

The pool is crystal clear right now with powdery green algae in the wrinkled areas in the deep end. small spots of visible algae growth in the shadows of the shallow end.

I am going to vacuum to waste and then see what you want to do.

OTO drops show 5 ppm FC. I read the instructions the other day that high chlorine can affect the phosphate test results, so I told her not to add any yesterday.

[PoolDoc]

I tested the phosphate level with the both. The Natural Chemistry one shows over 1000 ppm for phosphates. The Aqua Chek one shows at least 300 ppm, maybe a little darker.

Interesting.

When I did the side-by-sides with the Taylor and the AquaCheck, I got similar readings below 1000 ppb with both. But above 1000, all the readings from the AquaCheck were the same. I'm some what confident of my results, since I started with tap water (about 3,000 ppb at that location) and did successive dilutions with distilled water. So, even if my starting value was off (not 3,000), I knew that each succeeding result should be 1/2 of the preceding one.

I wouldn't suspect Natural Chemistry of deliberately creating a kit that overstates PO4, but I would suspect them of not caring much when someone pointed it out. After all, having a kit that shows their product as being more effective than it is would help them sell product.

I'll be VERY interested, once you reach PO4<100 ppb, to see what the Natural Chemistry test shows.

BTW, I've revised the phosphate link above. It took me several phone calls to Kem-Tek (KIK) to find out what's going on. Apparently, they are slowly closing out the Kem-Tek brand and replacing it with the Clorox brand -- but KIK is blending and packaging all the products. Their chief chemist told me the products themselves are completely unchanged.

However, because Amazon has not yet distributed the Clorox products to all its warehouses, Amazon is showing the Clorox products as "temporarily unavailable" which apparently means "since we don't have the product in all locations, we don't want you to hold us to our normal shipping standards"!

[bluebayou]

on a side note, the pool filter was off since Thursday around noon apparently. I started the system on "filter" before vacuuming. One return was not functioning. After 10-15 seconds (about the time to realize it and to walk to the return) it started blowing green powder into the pool for 4-5 seconds and then clear water.

otherwise, I am going to use the Phosfree. It says run filter for 48 hours and then to retest.

[bluebayou]

after adding 1.5L of Phosfree 48 hours ago, the AquaCheck test shows about 100 ppm (definitely a bluish tint, but not matching the 200 ppm color). the Natural Chemistry test still shows greater than 1000 ppm.

yesterday, I checked on the pool at 11 am and at 3 pm. there was visibly more of the brownish powder in the shallow end.

It accumulates in the same patterns every time. could it just be a particulate and not living algae? I don't understand where it is coming from if its dead algae. I really don't understand how it could double the visible amount in the course of 4 hours if it was growing.

the powder isnt attached to the floor and it brushes away with movement, but there will be obvious green growth under the powder (sometimes).

Saturday at 8 am there was very little material in the pool and the OTO test showed 10 ppm. Sunday at 3 pm the OTO test was maybe 4 ppm.

I am thinking about increasing my regular FC amount to 6 ppm. previous years I have just been around 3 ppm, but the CYA from test strips was less than 30. 10 ppm seems to be the breaking point for algae growth (not the brown powder, but greenish tint to the water and green algae on the sides and ladder).

[PoolDoc]

1. Order the Taylor kit; using successive dilutions with distilled water, I validated it against the AquaCheck kit, and they correlated well at the lower levels. I'm guessing the Natural Chemistry kit is bogus. Remember, they'll sell more if it consistently reads high! http://pool9.net/tk/.

Tip: get some sticky putty (Scotch brand @ Walmart) to hold the Taylor test cylinder. It's really tall and easy to tip over. A bit of sticky putty to set it on will make the test go much more smoothly. And use a TIMER for the wait period -- otherwise it's too easy to get impatient.

Regarding the powder - I haven't re-read the whole thread: did we ever suggest, or did you ever do the DE test? It would confirm or eliminate the filter as a source of problems. Plus, if you hand vacuumed the powder while DE was in the filter, you could be sure of capturing the dirt. And, if there is live algae in the pool, it will tend to rapidly stop up the DE and thus your filter, giving another indication. http://pool9.net/de-test/