That is very strange. I'm dosing pure DIY version, not TM's but mine with maximum possible concentrations of calcium formate. Never had such precipitation. If the product is super concentrated some crystallization is possible if the temperatures are very low, which I doubt is your case.It does appear that way. I think its a result of the solution "crystalizing" in the tube. I've been searching all day and it appears that this is quite common despite some never having an issue after years of use. Quite strange. If I cant solve this in the next week or so, I think I'm going to go back to hand dosing and consider my options.
If the outlet is close or touching the water some buildup of calcium carbonate will appear in time, but it is only on the tube opening.
During crystallization of the calcium formate no gases will be generated! If there are gas bubbles and there is no air leak there is chemical reaction happening presumably with a base forming calcium carbonate, formate and carbon dioxide. But in this case precipitation of the calcium carbonate will happen in the container/bottle also and will form kind of Coral Snow precipitate - like fine white "mud" not big crystals and all the solution will appear cloudy.
This is very helpful. Wouldn't want to ruin the solution.
There is no problem to dilute the solution. The mold will appear in concentrated solution also if is not sterilized properly or if there are no preservatives added. I did several experiments when I've tried to commercialize the product with various ways of preventing the fungus forming with mixed result (sometimes funny).
But for the test you can dilute only small part of the bottle say amount needed for one week and to see if crystallization still occur. Just use RO/DI water for dilution even small residue of alkalinity will precipitate calcium carbonate. And boil the water in microwave before dilution.
If crystallization occur only in tubing, then replace tubing, but not just with new one but with other type/brand, just to be sure it is not material of the tube causing precipitation of carbonate.
Sorry quite a long writing, hope it helps