THe polyquat, the citric acid, and the metal sequestrant tend to cause high chlorine demands, so you may have to supplement the SWCG with bleach to get the chlorine to register, at first. If you don't overcome it pretty quickly, though, you may need to shock the pool since keeping the chlorine at low levels for very long will allow algae to bloom. Putting a trichlor puck in the skimmer will add chlorine, assist your metals in precipitating out onto your filter, and keep your pH on the low side, so I don't see a reason why you couldn't use it.

Also, you might want to check your owner's manual regarding your CYA level--I think most SWCG manufacturers want 60-80 ppm of CYA in the water to assist the cell in operating the most efficiently--and low CYA may also be why you're having trouble keeping chlorine in the water...

One statement you made doesn't make sense to me, though--you said that the pH of your water falls when you add new water, so you're also adding Muriatic acid? If the pH is falling, you want to add Borax to raise it--MA will only bring it down further.

Janet