How far can I drain my "swamp"?

[poolgoat]

I bought a short-sale home last summer that features an AG pool (2yo liner). They had winterized it the year before and never took it out of hibernation, so it was a large pool of algae when unsheathed. 12 inches of visibility, tops. We had a pool guy come to explain the equipment (all tip-top, and there's even a bottom vacuum shark). He instructed us to pour giant buckets of chlorine in and keep the filter running non-stop, cleaning the filter non-stop, until it ran clean. This was tough going (took me a while to figure the "trick" to open the filter without my husband's brawn, so it couldn't be changed frequently), and then we went out of town for a weekend, and - long story short - after a few hundred dollars, it didn't look ANY better. (I tried flock, too, and didn't see any difference.) By that point, it was "winterizing time" anyways, so we decided to give up until the spring.

With the first freeze, the algae must have gone into remission, and I could actually briefly see to the bottom (!!), so I'm pretty sure that there isn't anything terrifically scary beneath the water, but lately it has been warm (in addition to other weird weather), and the green has turned less algae-like and more like chlorophyll. Thick, green, NASTY... maybe 3 inches of visibility, if the sun is right. I've searched this site, and it looks at least as bad as the "worst pool ever" posts. Surprisingly, it doesn't smell rank. Neither are there any apparent insects/ creatures breeding in it.

I will declare it a major miracle of chemistry if this water can actually be cleaned, but if it weren't for the liner it would certainly be cheaper to drain and refill than those expensive chemicals. I bought many bottles of bleach, having read that this can be a substitute if used at night. (I also have some algacide purchased for cheap at a hardware store closeout.) I see previous posts that have tackled similar problems. I guess my two main questions are:

1) It's going to get cold again, so I won't start my attack for a few months, but how long should this cleaning take? A week? A month? (Do I shock every day?) I need to know to plan my attack when we won't be going out of town so I won't be starting from scratch.
2) How much water could I safely drain the pool? I'd rather dilute it as much as possible. It's just so impossibly nasty.

I really appreciate your feedback and well wishes.

 

[JohnT]

Welcome to TFP!

It should take about a week to clean it up. They key is testing and adding chlorine much more often than daily. Most here recommend HOURLY additions at first, then backing off to every 4 hours after the first few hours, then 8 hours as the algae starts to die. The algae really consumes the chlorine that quickly!

Here are a couple of links to read:

Defeating Algae

Turning Your Green Swamp Back into a Sparkling Oasis

Shocking Your Pool

You also need to be aware of the chlorine/CYA relationship to determine the appropriate shock level. Chlorine CYA Chart

The key piece to the whole puzzle is being able to measure your chlorine while it's at shock level. That requires a more advanced kit than most non-TFP pool owners have. There are two commonly available options. The Taylor K2006 (not the 2005) or the kit that Dave sells at tftestkits.net. Either one will pay for itself in your first year of use. The key test that these have is the FAS/DPD chlorine test that can measure chlorine levels up to 50ppm.

 

[poolgoat]

Thank you so much for your response!

I was not able to find in the articles any indication of how safe it is to drain/ refill the pool? I intend to buy the testing kit that you mention, but with the richness of this green, I assume that the numbers are astronomical. I did see the phrase "replace water to bring the CYA level down to 90 or lower before continuing", but how low is it safe to go?

I know that it will be hard work, but I am really "looking forward" to seeing the problem solved!

 

[JasonLion]

You can drain until there is one foot of water at the shallowest spot without any risks. An above ground pool can be completely drained with some additional care. If you do completely drain, there is some chance that the liner will shift and need to be repositioned, or the walls might fall over and need to be reset, not the end of the world but annoying.

As long as there isn't any significant debris in the pool, say several inches of dirt or something like that, I would only drain enough to get the CYA level back to something reasonable and let chlorine take care of the rest.

 

[JohnT]

I assume that the numbers are astronomical.

Without knowing your numbers, there is no reason to drain. The nastiest, smelliest, blackest water can be cleared with just chlorine and patience. No draining required. What you need are test results.