UK pool Owner What is this??

[ajmooseman]

Morning all first post so be kind

Well i've been a pool owner for just sort of 2 years, which is when i moved in to the house.
The pool is a outdoor inground 36ft x 16ft hooper style bottom.
Since moving in we have installed a dome cover the type that you can swim under and also slide back when the sun does actually shine? As well as a fastlane swim machine.
Also has the filter sand replaced.
Pool is heated and this year I installed a biomass boiler to keep in nice and swimmable all year (was quite an interesting project)
I've also done alot of work around the pool which is when my troubles started.
In spring last year I had a whole pool area relayed with a stone resin (sometimes called stone carpet) while the builders were doing the work the pool developed a yellow coating to the base of the pool, I assumed this to just the dust from the sand they were using, anyway I hoovered the stuff away and within a few weeks the pool was clean and clear, periodically i would find small areas of what i thought to be sand accumulate on the seam of my pool liner and in a low circulation area. i would hoover it way each week, this stuff was so fine and dust like when yo disturbed it with swimming it was hardly noticeable.

I kept the pool open throughout the winter but without any heat, (as Triathlete wetsuit swimming suits me!)

All things where going great with the pool in early spring then one week I returned home from working away for a few days to find the pool looking yellow, on inspection the water water clear but this dust like substance had returned to the bottom of the pool fully covering the bottom, mixing the water up just made it milky and cloudy but the residue would settle within 24hours and form the same layer of yellow ish dust. after many different chemicals i eventually had to vac to waste to get rid of it wasting a lot of water. I vac'd to waste every night for a week. That was in June, now in September the stuff has started returning, i noticed a small amount and vac'd to waste about 3 weeks ago, it then returned within a week, now it's returning overnight. I shocked the pool Monday to see if it would work but nothing.

Yes I've rambled on to long and probably not covered any of the basic you need to help but I've got photo's

 

[duraleigh]

That looks like dead algae to me and is a result of inadequate chlorine.

Can you post a comprehensive set of test results?

 

[Caco]

Hi, great first post, lots of info and photos
But yes we will need some more information from you

First of all can you please fill in your signature so we can easily find your pool statistics and which county you are located in. Some of our advice may be area specific and cornwall is a lot different to dumfries http://www.troublefreepool.com/content/165-getting-started

Second it sounds like you have never really got rid of your algae bloom. We do this by following a process called a SLAM. The critical part is raising the pool to a shock level based on your CYA level and keeping it there until the testing confirms all the algae is gone http://www.troublefreepool.com/content/125-slam-shock-level-and-maintain-shockingl

Have a look at this chart to see what FC levels are required at what CYA levels and things may start to make sense
http://www.troublefreepool.com/content/128-chlorine-cya-chart-slam-shock

Third how are you testing your pool chemical levels? We generally rely on people undertaking their own testing as it tends to be more accurate and reliable than pool store testing. I would suggest having a look at amazon or ebay or similar and see if you can get a Taylor K2006C. It has the FAS DPD test and CYA testwhich you need to test the levels of chlorine you are going to need

Fourth dont worry about the cost of the kit. You will make that back easily with a lower amount of chemicals used and you can purchase most through your local supermarket, hardware or big box type store, instead of buying expensive pool speciality products which usually just have fancier packing, ie baking soda is the same as TA up http://www.troublefreepool.com/content/123-abc-of-pool-water-chemistry

Fifth we calculate how much of what to add by using pool math at the top of the page. Have a play around with it to get familiar with using it

Sixth have a read around the site in the forums and pool school and keep posting your questions back here. It should be fairly easy to clean your pool once we have good test results. Often the mods around here have to start with a completely dark green pool

Oh and welcome to the forum

edited:
lol Duraleigh, straight to the point

 

[ajmooseman]

many thanks for the replies , sorry for the delay in mine, I've been working away and also trying find out the information you require. Because i inherited the pool when i bough the house I'm not totally sure what all the kit is:

In West Yorkshire UK
Pool is in-ground 35'-16' with liner it's close to 20000 gallons and it's covered by and Abrisud dome.
Has 1 skimmer and one inlet (additional inlet blocked up)
Heated by Biomass boiler
Sand Filter quite large maybe stands 21/2 - 3 feet tall. Had 25kg of new sand and laterals in Feb2015
Pump is a Certkin Aquaspeed, 1hp i think?

Water test, i bought a Aquachek True test which only does the 3 tests, I've looking for the Taylor product but nobody seems to sell it here in the uk, can i just by a test kit for the additional 2 tests i need? or I've been looking at the Lamotte Pro 7?


I'm guessing I can't do anything much until i get a CYA reading.