Seems I need to replace my T-15 cell. Getting a continuous low salt reading of 2600. Brought a sample of water to pool supply store, their reading was 4k. I have cleaned the cell and filters recently. This has been going on for about 2 months with a low salt reading. I've added at least 2 bags of salt in that time. Did get the number up to 2900 once but it's back down to 2600. Called Hayward tech support, went through the diagnostics. He recommended getting a new cell. After researching prices for a new T-15 I noticed it's for a 40k gallon pool. My pool is 10k-15k gallon. Can I or should I switch to a lower model of the Hayward or just stick to the T-15 or maybe another brand?