Trace can also be replaced with a few other products on the market. What that doesn't change is the TDS (total dissolved solids)
TDS helps with the KH or carbonate hardness. This helps buffer the PH keeping it from dropping due to waste build up. But what you need to know is most tap water that hasn't been run through an RO filter has TDS in it. As water evaporates these dissolved solids are left behind. When you top the water off you are adding the dissolved solids in the new water to what was already in he tank. Over time this is going to increase your TDS/KH/PH.
Think of it like this. You have a bowl, in this bowl you put 1 cup of water and in that cup of water there was half a cup of dirt. When the water evaporates out of the bowl you replace it with another cup of water half full of dirt. Over time you will end up with a bowl of dirt.
Water changes remove the old TDS and replace it with the new helping to slow this down. Even then without using RO water once in a wile, over a long time the TDS of a tank will still increase. |