Opening Algae Problem

[skinney1086]

I have an 18X36 ~25000 gallon in-ground vinyl pool that has a mesh cover. I've only owned a pool for about 3 years now. Still learning.

My problem is every year I open the pool it has a massive algae.

I have two questions.

1) What is the best way to clear this up?
2) Is there anything I can do to help prevent this in the future?

Thanks for your help.

[Watermom]

First thing is to get a good test kit. The only one we recommend is not available locally but if you will click on the test kit link below, you can order it from Amazon. (Taylor K2006 or 2006C which is actually the better buy.)

What kind and size of pump and filter do you have?

Do you have any test kit at all currently? If so, what? Do you have any water testing results?

What all have you used in your pool meaning ingredients and not just product names like 'shock.'

Do you currently have debris on the bottom of the pool?

Welcome to the Pool Forum, by the way!

[skinney1086]

Currently I'm just using the HTH 5-way test kit from walmart.

Pump: I'm not 100% on the pump. I believe it's a 1 or 1.5 HP Pentair Challenger.
Filter: Hayward Sand Filter

I actually haven't taken the cover off yet. I'm am tonight when I get off work. So I don't have any readings.
I didn't know how long it would take to get a reply, which is why I posted already. :-)

The past 2 years when I opened it was a full algae outbreak. It usually took about 8-12 (maybe more) gallons of "pool" liquid chlorine.

So I was just looking around to see if there was anything different I could do. Any advice is greatly appreciated.

Thanks

[PoolDoc]

1. Go to Walmart or equiv and get 16+ gallons of plain 8% bleach AND a cheap OTO / phenol red drops kit (HTH DPD goes to 5 ppm, and bleaches out somewhere between 10 and 20 ppm!)

2. Physically clean all algae piles and debris. Put pump on recirculate rather than filter.

3. Begin dosing your pool in 4 gallon increments. Retest with OTO after 4 hours of circulation. Repeat dose if chlorine level is less than DARK yellow. Continue this till pool goes from green to gray.

4. Brush the pool completely (even if you can't see!). Make sure the chlorine is DARK yellow before starting. Pool may go green again. Check chlorine after 2 hours -- repeat dose if not DARK yellow.

5. Hold chlorine high 24 hours after brushing. Allow chlorine to drop to 5 ppm. Add a SINGLE dose of whatever clarifer or liquid floc you have on hand. Circulate per instructions, or for 4 hours. Turn pump off overnight.

6. See if algae is going to settle. If it does, let it settle for 24 hours. Maintain chlorine via direct additions. Vacuum piles to waste.

7. Once you've vacuumed what you can OR if it's not settling, turn pump on and begin filtering. Wait at least a week before adding any more clarifier. Do NOT use a 2nd dose of floc.

8. Once you can see your pool returns, you can add a small amount (2 - 3 cups) of DE filter powder to a skimmer. If a cloud shoots out of a return, your filter needs work. If not, you can use repeated small doses of DE to help remove the algae . . . but it will force you to backwash much more frequently.


===========================

How to avoid this? Ask after July 4th.

[skinney1086]

Awesome!! Thanks for all the information. That is pretty close to what I have been doing the past couple years. Last year was the first year I tried the DE filter powder, which seem to help a lot.

I'm hoping my filter is fine. I just replaced the sand in it about half way through the season last year. I was having to back wash a lot and that is what the local pool store recommended, which after doing that things went back to normal. So I guess they were right on that one. :-)

Well I got the cover off tonight and here are my first readings using my HTH OTO 5 way test kit.
FC: 0
pH: 7.2
TA: 60
Hardness: 150
CYA: 10
Water Temp: 74

Does any of those readings change the course of action you have listed out?

Also my local Wal-Mart has HTH liquid chlorine 10% in a 2 pk of 1 gallon bottles for $5.99. So from what I have been reading on here that would seem to be a lower cost per active oz. Since it's 10% I guess I would only need around 12 bottles of it? If my math is correct.

Would you recommend using HTH liquid chlorine or just stick with plain bleach?

Also I've been reading some of your BBB method. I think I might give it a try this year. Just need to read up on it some more to make sure I understand the process I should follow.

Thanks again for all your help.

[skinney1086]

Correction on my equipment.

Pump: Pentair 1HP
Filter: Pentair Tagelus TA-60/600 Sand Filter
inline Hayward auto chlorinator

[PoolDoc]

Plain bleach is much more likely to be fresh. That is less of an issue now, than once it gets hot. But if the HTH has been sitting around . . . it matters now. I'm not sure what you're paying for the 8% store brand Walmart bleach, but the prices here would make it, not the HTH 10% cheaper.

[FormerBromineUser]

How is your pool doing? Did you decide to use the BBB method? If so, did you buy the K-2206 test kit?

[skinney1086]

The pool is doing awesome this year! Yes I have been doing the BBB method all year with great success. I did buy the k-2206 kit and does seem to be a lot more accurate then the OTO kit.

[skinney1086]

Hi Mr. PoolDoc,

I forgot you asked me to hit you up after the july 4 for the information or steps I can do this year to help prevent a big algae problem next year when I open my pool.

So is now a good time? :-)

Scott

[FormerBromineUser]

Nope... PoolDoc's father passed recently and he is taking a hiatus from the forum and will hopefully be back soon. I know he was working on a new closing system but in the meantime you could read some RECENT (2013) posts about closing. So glad you got the K2006 and are loving BBB! Let us know if you need anything!

[PoolDoc]

Actually, yes . . . with the understanding that it's a TRIAL. I've seen good results in my local use and testing, but this approach is new to the PoolForum.

Basically, it involves the following steps:

1. Clearing your pool from all existing algae with high chlorine. This can be done with the pool partially covered (or fully covered, if you have a mesh cover).


2. [OPTIONAL] Raise borates to 60 ppm. On your pool, this means 25 boxes of borax and about 8 gallons of muriatic acid. Note that this is a PERMANENT addition. The borate is removed only by draining (or leaking) water from your pool. Evaporation has no effect. So, if you raise borates this year, you'll only need to top-off in coming years, unless you drain and refill the pool.

Borates > 60 ppm are a weak algae and bacterial inhibitor. It make a noticeable, but not huge, difference. Other effects include "sparkly water" (changes the refraction index a bit) and more "comfortable water" (somewhat like the effects of adding salt).


3. Test and lower phosphates (PO4) to 100 ppb OR LESS.

This is a BIG change here. I've counseled against phosphate removers, because they were overpriced and usually ineffective. It turns out the reason is that phosphate removers are useful ONLY if you lower levels to 200 ppb OR less. If you lower PO4 from 4,000 ppb to 1,000 ppb and stop . . . you've totally wasted your money.

During the pool season, it can be difficult to maintain low PO4. Refill water from the hose often contains 3,000 or even 5,000 ppb PO4. But this is not an problem once the pool is closed.

Also, it turns out that there is a concentrated phosphate remover (Orenda PR-10000) that is reasonably economical IF you purchase it carefully. One quart can be purchased for $55 delivered, and will remove up to 3,000 ppm from your pool.

For your pool you need at least 3 quarts of PR-10000 (even if you don't use them all!) and a Taylor K-1106 testkit.

PLUS, you need 2 weeks. For reasons I don't fully understand, the TOTAL amount of PO4 in a pool typically seems to be higher than what appears in the water when you first test. I suspect that -- initially -- the PO4 in the fill water 'coat' all surfaces, including pipes, filter sand, liner, etc. (This coating effect helps prevent metal corrosion, which is the reason for adding the PO4 in the first place.) Once you lower the PO4 in the pool water, the PO4 attached to all pool surfaces re-enter the water . . . and have to be removed.

So, to remove the PO4, you have to lower the levels a LOT (> 500 ppb), and then keep adding smaller doses of remover, till levels drop below 100 ppb and REMAIN there. This takes time.

The effects of this treatment CAN be permanent, but ONLY if you continue to add small doses of phosphate remover EVERY SINGLE time you add fill water. (Rain water may, or may not, add PO4. The data I have is conflicting: you'll need to test and see.)

BENEFITS: very low levels of PO4 (< 100 ppb OR 0.1 ppm) slow algae growth greatly, and bacterial growth somewhat. This makes it MUCH easier for biocides (like polyquat) or sanitizers (like chlorine) to kill the algae or bacteria. Combined with low water temps, low PO4 levels should result in greatly reduced problems with opening.


4. Test the water 'balance' factors with the K2006. Adjust pH and TA as needed to establish a slightly negative saturation index, to avoid problems with scaling.


5. ONCE
=> pool water temperature is below 70 degrees,
=> water is completely clear,
=> pool is completely algae free,
=> saturation index is correct, and
=> PO4 levels are below 100 ppb
THEN cover the pool fully.


NOTE: Winterization can be paused at this point, and the covered pool can be operating in this state for weeks, if needed. Keep chlorine levels in the 5 - 10% of CYA while doing so. Monitor PO4 levels, however.


6. [OPTIONAL, but recommended] Put filter on bypass (or remove cartridge or DE powder) and add 10 ppm of polyquat (about 2 quarts on your pool) to your pool water. Circulate for 2 hours before finally closing pool.


7. Shut down system, and winterize pool piping and equipment.


8. Inspect under pool cover monthly, during months when pool is NOT frozen, using a water proof flashlight. At the first sign of slime or cloudiness, dilute polyquat in water (1 gallon per quart) and add to pool at 4 corners.


9. Open pool before water temperature exceeds 70 degrees. Test pool water before opening. IMMEDIATELY add a chlorine dose equal to 20% of the CYA level.


. . . . anyhow, that's the plan.

I'm going to be offering a limited number of 'kits' containing (3) quarts of PR-10000, (1) quart of polyquat, a K-1106, a calibrated pool thermometer and a registration and instruction package, so users (and I) can track results online. It looks like I'll offer this for about $225 delivered to 48 states.

The package will be available ONLY to pool users with a K2006, who are willing to participate in the trial. I will create a special forum section for discussiing these results, and set up automatied reminders (text / email) of winterization milestones.