I'm maintaining a pool that my family use at a rented property. I know I have a number of important equipment limitations but given we are renting it doesn't make sense for me to invest in any permanent improvements. Let me explain what I have, then I'll continue with my question:
- Pool size: Aprox 48,000 liters
- Material: Plaster (i assume, it's painted)
- Pool has no permanent circulation/filtering equipment
I have purchased
- 3/4 HP pump (i connect this up when i use it)
- Vacuum head and necessary pipes (when i vacuum pool this water is thrown away and then a refill as required)
- Simple OTO/PH drop based test kit
- Some 3-way HTH test strips that include total alkalinity (I live in Argentina and have found it impossible to get any decent test kit yet, i bought these strips just to get an idea of total alkalinity.)
- PH 8+
- Total alkalinity appears to be around 300 given it turns test strip blue not green.
- Pool was filled with this water about 4 mths ago
- I'm now using bleach (10%) exclusively
- In the past 4mths i've used di-cloro granulated a lot (probably 8kg in total) and 1kg of pucks. I know this is a a lot but given that i must throw out some 3000l each time I vacuum I'm assuming CYA can't be too high.
Me problem/question is the following:
I've been maintaining this pool ok for about 3mths and everything was fine but then water gradually got clouder and clouder even though i was still using the same amount of chlorine. In hindsight this was probably caused by the fact that the PH was creeping up with oxygenation and new fill water being added and the chlorine was less and less effective. Also during this time the water temperature went up from around 21C to around 28C (summer started, i'm in southern hemisphere).
I applied a shock treatment of chlorine (10l of 10% bleach ) but cloudiness remained. Unsure if it was an algae problem or just dirt in suspension i used a clarifier. This made the water look clearer but also meant i saw small coin-size green patches on the surface and larger irregular patches of green on the bottom of the pool. I vacuumed the apparently loose sand-like stuff up from the bottom of the pool but the next day it was back again. I realized this might be a PH issue and when I measured it it was around 8 so I shocked again after lowering PH to 7.6/7.8. A lot less sand-like greenish stuff reappeared on the bottom of the pool (a bit does though, not sure it if dirt, precipitated remains of algae of live algee), the chlorine when measured in the morning was still above 5ppm and the shallow-end looks looked very clean/clear. The problem is that at the deep end of the pool (2m) although i can now clearly see the bottom now and the water when using the pool looks clear, when I look at the pool from a short distance the water at this end of the pool still looks somewhat cloudy and a bit blue-green (a lot more so when look at it from an angle rather than straight down).
Yesterday i lowered ph even further to 7.3 (6kg of dry acid hoping that i'd also reduce TA a bit and improve the PH creep issue) and shocked again (7l of 10% bleach assuming CYA of 50) but didn't notice any improvement this morning.
Am i over the algae bout? I'm not quite there yet and need to keep shocking? Or you can't help much because i have such poor pool/test equipment (hopefully you can still give me some pointers)?