I have a large number of Rainbow 300-29x offline and 320cn inline feeders in use at various pools. Some of these pools are very old and have minor unlocatable air suction leaks, causing small amounts of air to travel through the line. Some of this air ends up in the chlorine feeders, in some cases dry-locking them (no water flow). In one case this happens on a daily basis; others it is slow or random.
Has anybody ever added something to these to remove air? Irrigation systems have a simple check device which allows air to escape the line, but seals shut when water hits it (via a floating ball). Would this work, installed in the lid or in a new port slightly higher than the return line, or might it allow chlorine gas to escape too? I tried installing one in the line to the feeder, but it didn't catch any air.
Any other ways I can solve this?