Pool dust/algae-how to tackle

[Guest]

I have a quick set 16 x 36 pool. I have a dust type of algae thing going on at the bottom. Tried and tried to vacuum but it would just stir up and then resettle. I have read some great tips on how to resolve but my question is in what order do I need to do everything? I shocked the pool last night, tested this morning and my cya is at 0, ph 7.2, alk 120 but the fac is still 0. Do I need to raise the cya before raising the fac? Then shock and/or bleach before adding clarifier to be able to vacuum the particles on the bottom or does the clarifier go first? I'm not sure in which order I need to start.

[Losing my tan]

Sorry, didn't realize I had to log in first

[chem geek]

If your CYA level is truly zero, then yes, you need to add some and the easiest and fastest way to do that along with adding chlorine that you also need is to buy some Dichlor powder/granules since for every 1 ppm FC added from Dichlor you also add 0.9 ppm CYA. Unlike pure CYA, Dichlor dissolves quickly. So I would just start using Dichlor and keep track of how much you use and stop when you've added about 33 ppm FC worth. One pound of Dichlor (dihydrate, the most common form) adds 6.6 ppm FC and 6.0 ppm CYA in 10,000 gallons so you can scale accordingly based on the size of your pool.

If you have zero CYA, then you must have not been using Trichlor tabs/pucks and instead must have been using only bleach or chlorinating liquid or Cal-Hypo granules (or HTH Duration tabs), right?

So add the chlorine and CYA via the Dichlor first. The chlorine should start holding and should shock the algae as well. Try and maintain at least 10 ppm FC. When you get to 30 ppm CYA, stop using Dichlor and switch to unscented bleach or chlorinating liquid. You should then maintain a 12 ppm FC shock level until the algae is gone, you see no drop in FC overnight, and you measure no Combined Chlorine (CC). If you do not already have one, get a good test kit, the Taylor K-2006 you can get from Taylor here or from Leslie's here or the even better TF100 test kit from tftestkits here.

You shouldn't need the clarifier unless the cloudiness does not clear from the chlorine alone. You may need to clean your filter -- check it and see if it needs cleaning.

Richard

[Losing my tan]

I was using chlorinating granules and had the hth chlorinating tabs in a floater. I think my problem was I didn't keep up on the stablizer/conditioner and the chlorine was just getting sucked up???? So after I use the Dichlor, do I clarify to be able to vacuum? Or then can I bleach and clarify closely together? I am just confused on when to keep the fac up and hold it for 24 hours to kill the algae. Does this make sense?????

[Losing my tan]

Thank you so much, I am heading to Leslie's right now to get Dichlor and a good test kit. I changed the filter before shocking last night, but have plenty on hand to get through this.

[chem geek]

Yes, if you used Cal-Hypo chlorinating granules and Cal-Hypo HTH Duration tabs, then you were not adding any CYA so the chlorine was not protected from sunlight. You normally don't need to add more CYA if you add it initially unless it gets diluted from splash-out and backwashing. Anyway, the Dichlor will add it for you.

The Cal-Hypo also added to Calcium Hardness (CH) so you should check on that level as well, though it's probably OK since you don't need a lot of calcium for a vinyl pool and it takes a lot to get too high. CYA is much more sensitive in that way as a smaller increase is a bigger problem compared to CH.

After the Dichlor, see if the water clears on its own via normal filtration and chlorine breaking down what's in the water. If it doesn't, then you can add the clarifier to see if it helps (since you've already bought it -- otherwise, I'd have you use OMNI Liquid Flock Plus instead, but again only if the water does not clear from filtration and chlorine alone).

You keep the FAC up until the following three things all happen: 1) the pool gets crystal clear with no cloudiness nor visible algae, 2) you measure minimal drop in FC overnight and 3) you measure no Combined Chlorine (CC).

[chriskrystalj03]

I am having the same problem. I didn't winterize my pool last summer *was the 1st year I had it* and when I got ready to open this year it was green w/ algae. I have spent over $150 on chemicals and now have a white substance on the bottom. When I brush it disappates. When I vaccum it is coming right back into the pool and settling on the bottom. According to the pool supply store my pool is balanced but my chlorine reading is EXTREMELY low and I have shocked several times, I have 3 3" tabs in the floater and one in the chlorine dispenser on my filter. I have a cartridge filter.... Any ideas???

[chem geek]

You really need to get your own good test kit such as the Taylor K-2006 kit you can get for a good online price here or the TF100 kit you can get from tftestkits(dot)com here with the latter having 36% more volume of reagents so is comparably priced "per test". Because the amount of chlorine you need depends on your Cyanuric Acid (CYA) level, you reall need to test for it. Read this sticky for how to clear your pool.