RE: In-Ground, DE Filter Pool With Clear Green Water

We have an in-ground pool that up until recently has had very few problems. This pool is at least 30 years old but has been maintained well the whole time. We re-plastered when we moved in 8 years ago, and it probably will need to be done again next summer.

DE filter, polaris in pool vac with a boost pump. Main filter runs 4.5 hours per day.
Not super sure on the gallons, we think about 35,000 maybe, but it's irregular shaped so it's tough to get a perfect number. I suppose refilling with a meter on the hose would be the best method, can do that when we re-plaster.
About 9' deep, maybe a little more, it used to have a dive board. Auto cover, used most of the time, and a new solar heating system.

Anyway, we've been using the pucks in the floating dispensers, three dispensers and 2-3 puck each depending on the temperature and pool usage. We usually backwash 2-3 times a year, spring, couple times during summer, and sometimes one in fall.

But last year due to some personal stuff, we didn't backwash for about a year. When we back-washed at the start of the summer this year, we realized the DE filter panels needed replacing. Did that and figured we were good to go.
However, slowly we started to get green water and it's been really stubborn to get rid of. We tried upping the pucks but it didn't help, tried some powdered shock about 3 different times, it didn't work. Have not tried liquid chlorine yet.

We test with a small kit that just measures free chlorine, combined chlorine (not sure what that is) and pH. The drops are fresh, but I'm now realizing it's limited. We did find the pH too high,(we thought it was according to the test) at 7.8 and added muratic acid to lower it. It's now kinda too low at 6.8

Just tested now; Free Chlorine 0.6, Combined Chlorine between 1.0 - 0.6
pH 6.8
KH 107.4 ppm

Don't know if KH is important but I had the test kit from an aquarium so though I'd throw it in there.

Seem like it's just too low in Chlorine, but we get this low reading even after refilling all 3 floaters. It's like the chlorine is either not dissolving into the water, or maybe dissipating too quickly. I haven't used liquid chlorine.

I just ordered a new Taylor k600a test kit, so that should help me get a handle on this.

I've also read here that we should be using some kind of stabilizer, pretty sure we haven't used that at least on purpose. It may be in the chlorine pucks but I don't know.

The water is pretty clear, just green. Although since the pH has been low, there's also a slimy film on the water.

Any suggestions or ideas would be really appreciated. Thanks for listening.

Barb

Do you have steel (iron) pipes? (IMPORTANT QUESTION: Find out, if you don't know.)

Regardless, report your test results, ASAP, when you get your K2006 . . . AND do all these things:

1. Run your filter 24/7 -- on low if you have a 2 speed.
2. Add borax (20 Mule Team Borax from Walmart, etc.) 2 boxes at a time, to the skimmer. Do not CHOKE the skimmer. Test pH 4 hours later. As soon as you see the slightest pH increase, drop to 1 box at time. Stop when the pH reaches 7.2 - 7.4
3. Get some polyquat (info) ASAp and use it.
4. Maintain chlorine levels but do NOT add a large amount of chlorine at once.

Looked up KH => carbonate hardness. It's relevant info, but not in isolation.

Thanks for the reply.

I used 3/4 of a box of borax before I read your reply and got the pH up. How much I'm not sure because I got 3 different readings from 3 different tests.

Pool phenol red test-7.8 + two aquarium tests: for reg. pH-7.0; for high pH-7.4. But even the low one is better than it was. I can add the rest and get some more today, but I still won't be certain what the actual pH will be. I can see now we were kinda flying blind with such a limited test kit.

I added two gallons of 10% liquid chlorine and got the level up to 1.0. Next I added the Polyquat 60% according to the instructions. We backwashed before the borax and once more before the chlorine, but not after the Polyquat,and brushed down the sides.

We ran the pump 24hrs. after the chlorine addition, but I'm having a bit of a hard time convincing my husband to let it run that 24/7 longer than a day.

Pool temps have been about 84*F

We don't have iron pipes, they're copper or pvc with the exception of a 2' section in the filter shed.

Looks like my test kit will arrive between the 3rd and the 8th. Hopefully sooner!

We are hosting my grand nephew's 2nd birthday party on September 1st with a parent/tot swim party and really need to get this dialed in by then.

I really appreciate your time and advice!

OK. Just hold the low chlorine (1 - 3 ppm) and moderately low pH (7.0 - 7.4) and run your filter as much as you can. Dose with the polyquat ever 3 days. As soon as you get the K2006, post your results.

I hadn't realized you had a DE filter, till I inserted your signature just now. That means it's unlikely the problem is algae, since live algae stops up DE filters very quickly. With copper pipes and low pH (below 6.8), you may have very high copper in your pool water. Testing may, or may not, reveal that. If it is copper, the solution is
1. stop adding it -- keep the pH above 7, so you don't dissolve any more copper from your pipes.
2. keep it dissolved so it doesn't stain the pool -- use HEDP
3. remove it using the CuLator packs.

If it is copper, there's a good chance simply adding HEDP will turn your pool to near-blue. But even though HEDP is often marketed as a stain remover or metal remover, that is NOT what it does. HEDP just keeps dissolved metals dissolved, and helps prevent chlorine + higher pH from turning the dissolved metals into stains.

To actually REMOVE the metals, you either have to use the CuLator product (a special water-softener type material) OR you have to filter the metals out. But, to filter them, you have to precipitate them -- make them UN-dissolve, and turn them into particles . . . OR stains! The CuLator is a LOT easier, since it can 'take' the metals away from the HEDP. The downside of the CuLator is that it works slowly, and you have to use HEDP the whole time, to prevent the metals from staining.

Anyhow, you can wait till you have your test kit, so we can do some more checking to verify that it really is metals, OR you can go ahead and order both the HEDP and CuLator paks, so you have them waiting for you, and ready to use as soon as we're sure. I'll put links below, so you can go ahead, if you like.

Ben

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HEDP is a liquid phosphonate that is pretty chlorine stable, and very good at keeping dissolved metals IN the water, instead of ON your pool surfaces. It can lift recent stains, OR it can be used along with ascorbic acid, to keep the metals in the water, after the ascorbic acid is consumed by chlorine.

Jacks Magic The Pink Stuff 1qt (60% HEDP) @ Amazon
20% KemTek HEDP @ Amazon

The CuLator product is a special patented plastic material, contained in a bag that goes into the skimmer, that can slowly take metals OUT of your pool water. We think it works, and have some evidence that it does, but not proof yet. (Not likely to be available locally.)

1 ppm Culator @ Amazon
1.5 ppm Culator sold by Amazon, shipped from Periodic
4 ppm Culator sold by Amazon, shipped from Periodic
Poolmaster 16242 Poolmaster Skimmer Basket Liner @ Amazon (to protect CuLator from being damaged by scum)

OK, I put in the polyquat and brushed again and it looks like there is/was some algae growing on the surface, it came up when I brushed. So I probably have both copper and algae. Since the last backwash before the 2- 10%chlorine gallons and the polyquat, the pressure on the DE filter has risen a few points; from the 20-24psi it usually runs, to about 29psi. That happens when it's gettng clogged I think, so it may be fitering out the dead algea. We will back wash again this afternoon after the brushed algea/whatever goes thru it for a while. We are adding couple inches of water at the same time as it went down a bit with the cover off so long; it's been pretty warm the last few days.

Then after the brush, and backwash, we'll add another gallon 10% liquid chlorine and keep the filter on and shut the cover for tonight. I'll test again in the morning.

We have 32oz of Leslie's Super Metal X which according to it's MSDS sheet is 2-phosphono-1,2,4-butanetricarboxylic acid (28%). Sound similar to the HEDP you mentioned, but not exactly. Do you think this is the same thing? If not, I'll get the HEDP.

We do have some pretty bad staining on the steps and a few other places, so I wouldn't be surprised that we would have copper in the water. Also the fill line is galvinized steel and does dump rust water for the first couple gallons. We hold a bucket under it until it comes out clear, but I bet previous owners may not have done that.

Those CuLator packs sound great! I don't care if they work slowly, as long as they get rid of the metal instead of just dissolve it. I'll get some of those too.

Since the polyquat and brushing all the algae(?)stuff(?) Copper(?) or combo has made the water cloudy, but I think it will filter out. So that's my plan until I get the test kit. Thanks again for the great advice. I feel like maybe we can get a handle on this now. And I now realize how lax we have been about maintenence. We fired the pool guy three years ago cause we caught him billing for days he didn't come, and ironically we're pretty much doing the same thing up til now. That's going to change.

It looks like you need to get HEDP. I didn't realized the old Monsanta Dequest brand was still active; it's now owned by ThermPhos, and is documented at www.dequest.com. Any how, the properties I could find for Dequest 7000 (2-phosphono-1,2,4-butanetricarboxylic acid) mentions calcium scale inhibition, but not heavy metal sequestration or chelation. Usually, if a product desired property is NOT mentioned, it's not present.

Let me caution you that the stain removal process is VERY sequence dependent; do things out of order, and you can end up wasting all the chemicals you bought!!

Quote:

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Dequest® 7000
Title : Dequest® 7000
Synonyms : 2-Phosphonobutane - 1,2,4 - tricarboxylic acid
Cas number : 37971-36-1
Einecs number : 253-733-4
Product grade : Industrial
Description : Excellent Chlorine stablity and calcium scale inhibition in high stressed alkaline conditions.
Applications : Controls scale where halogen-based biocides or hypochlorite bleach are employed. Controls calcium scale formation in high stressed alkaline conditions.
Storage : Material should be kept cool and dry for best results.
Shelf life : 2 years
Packaging : Drum; Tote; Bulk
Safety : UN 3265 CORROSIVE LIQUID, ACIDIC, ORGANIC, N.O.S., Class 8, PG III


Dequest® 2010
Title : Dequest® 2010
Synonyms : 1-Hydroxyethylidene -1,1,-diphosphonic acid, HEDP
Cas number : 2809-21-4
Einecs number : 220-552-8
Product grade : Industrial
Description : Dequest® 2010, noted for its excellent CaCO3 scale inhibition and chlorine stability is based on hydroxyl ethylidene (1, 1-diphosphonic acid) and is approved for applications in which boiler steam comes in contact with food.
Applications : Noted for its excellent CaCO3 scale inhibition and chlorine stability. Only Dequest® approved in boiler steam contacts with food. Cooling water treatment, boiler treatment, I & I Cleaners, swimming pool, stain prevention, metal ion control.
Storage : Material should be kept cool and dry for best results.
Shelf life : 3 years
Packaging : Drum; Tote; Bulk
Safety : UN 3265 CORROSIVE LIQUID, ACIDIC, ORGANIC, N.O.S., Class 8, PG III
Manufacturing site : Newport

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Interesting. This was something that came with the pool, so it's probably old, I'll get rid of it, and get HEDP. We have a few bottles of this and that, that came with the pool. Everything that was from Leslie's Pool Supply did not have the actual chemical name on the bottle. Not one.
I had to look that info up on the web and found their MSDS sheet on a page not even connected with Leslie Pools. I think it's rather odd to package chemicals and not have the active ingredient anywhere on the label. Don't think I'll buy from them myself.

Thanks for the heads up on the sequential nature of the stain removal process. I will be careful. I set a vitamin C table on the worst stair stain, as I'd read it can be a good test to see if it's iron stain, and yep, the stain in that spot cleared up under the tablet. So, those stains probably are iron.

Interestingly, I have a koi pond also, and the best product for algae removal without hurting the fish or plants is the same ingredient as in the Polyquat, except at 4.5% strength. Works really well in fish ponds, as copper in any amount is toxic to fish, so good products can have lots of applications I guess.

Well, thanks for all the help. I'll post again when the test kit arrives.

Also, forgot to add, interesting that you only found that ingredient to take care of calcium scale, and not metals. Wonder why Leslie pools would name it Metal X in that case, hmm. Seems a bit misleading, to say the least. I can see now why most pool company products don't have a good rep here. lol.

You mentioned that you've been using trichlor pucks in the feeders, which do contain quite a bit of CYA and will raise it quickly. If you've been using the trichlor pucks for a long time, the algae growth is probably because the CYA has gotten too high and you're not maintaining adequate chlorine levels for it. I've skimmed through this thread a couple of times, and I don't see a CYA level listed...when you get your kit, please test for CYA and post that number.....

Before you do a stain removal process, check with me. I think I'm about to revise that process. In particular, you MUST have a full set of K2006 readings, especially including TA & CH.