Can you show us the results of some water tests? Like pH?
If you just have hard water I would expect that what you are seeing on the hydroton is actually minerals (like lime scale) building up and not necessarily salts unless you have salt intrusion into your well.
You can cycle up a system with hard water, I did.
Hard water will give you more problems with your plants than it will with cycling though if you haven't added any fish or started fishless cycling yet, you might use some acid to bring your pH down into the 7.2-7.6 range before you start cycling. I only recommend this acid use in the system if your pH is way over 8 and you have not added any living creatures, plants or started your cycle up yet. If you have started cycling or have any creatures in the system, then I would recommend you do your pH adjustment to your top up water in a separate container. I don't really like the acid use as a long term fix since it will put large amounts of the calcium or other minerals making your water hard into the water which can have other impacts on nutrient availability. If you can collect rain water to use for top ups at least part of the time, that would be a good choice or you may want to look into some RO filtered water so you are not constantly needing to use acid and release calcium into your water.
I am not to shur what minerals are in the city tap water that I use. my ph is at 7-7.4. the plants that I am starting with is spinch, I know they don't like getting splashed with the water because it has killed those sprouts due to the salt build up. When I use the term "salts" Iam using it as a catch all for all disolved minerals in the water.
Ok that pH reading on the tap water is probably a false low reading (I'm guessing here.)
If you measure the pH right after you pull the water from the tap, there is dissolved carbon dioxide trapped in it and that will act as a weak acid and give you a false low pH reading. If you take that same water and bubble it overnight and then do the pH test again, it may require the high range pH kit. My well water will read about 7 (varies by season though) right out of the faucet but once the CO2 escapes the pH is actually above 8. I live in FL the land of limestone aquifers and that is where my well water comes from.
The ph reading is from the fish tank. Where Thunder Bay gets its water from is lake Superior. I don't know which chemicals they use for treating the water. I started my system 4 weeks ago. I had 4 goldfish but am down to 3. I have yet to see any algy in the fish tank.
They often add something to the tap water to bring up the alkalinity a bit to help the chlorine or chloramine work better. A pH of 7-7.4 isn't especially high so I don't your water is all that hard. As the system cycles up keep an eye on the pH since if it drops too fast it can upset the bacteria so you want to have some shells or lime and potassium bicarbonate on had to buffer it a bit and provide potassium and calcium as needed.
The Bacterial action of the bio-filters will naturally use up the carbonates from the water over time, hence the falling pH and the need to buffer a bit (small amounts regularly is usually best since we don't normally want to raise the pH, just keep it from falling too far. 6.5-7.0 is the general target range.)