Should I ever perform a water change?
Under ordinary circumstances, you won’t need to change the water in an aquaponic system the way you would in a standard aquarium. However, certain situations can occur in which a partial water change can be helpful in addressing problems - particularly if you have too much of something in the water, like ammonia or nitrate. You may also need to change some of the water from time to time to reduce salinity and hardness; remember, mineral salts don’t evaporate like water does! You can drastically slow down the accumulation of salts in the water by replacing evaporated water with distilled or purified water, but once or twice a year, it’s a good idea to perform a partial water change anyway, since even feeding your fish will introduce some amount of salts. Always dechlorinate your water if it's coming from your municipal tap!
Do I need to clean the gravel in the aquarium?
An old-fashioned under gravel filter is an excellent accessory for your aquaponic garden. These filters use the gravel itself as a filter medium, and pull tank water down through the gravel into a chamber underneath. Since water continues to circulate through this chamber, it doesn’t become anaerobic and toxic, and the wastes can gradually break down to be used by your plants. If you don’t use an under gravel filter, it is a good idea to use an aquarium “gravel vacuum” siphon to clean out your gravel from time to time, or, if you don’t mind the mess, to simply turn on your pump and stir up the gravel to allow the wastes trapped in it to be pumped up into the garden bed where they can be broken down. Note: we recommend only using aquarium gravel. Do not use sand in the aquarium.
Is it normal for my clay pebbles to float?
During setup you installed drain risers that determined the water level depth in the AquaSprouts grow bed. If you notice your clay pebbles floating, it could just be that the amount of risers added is deeper than you need with a new, full-power pump, and the water level while the pump is on is high enough to float pebbles. If this is the case, you can either remove a riser from each drain, dropping the maximum operating water level of the bed, or you can use the slider on the side of the pump to adjust its output, slowing the inflow of water into the bed.
The pebble media can be pretty dusty after shipping, and if it isn't rinsed sufficiently, the dust can clump up and clog lines and outlets. Since your media is already in your Garden, rather than taking it all back out, you can take the Garden bed off the top of the tank, take it to the sink or outside, and rinse it thoroughly, especially around the location of the three ports (inflow and outflow), to try to wash out any clumps of clay dust.
Clay pebble structure varies, and some have more air trapped internally than others. Eventually, if they're in contact with water long enough, they should all saturate and stop floating, but this can take a long time. The operating water level of the Garden was designed to be low enough that it wouldn't float out these long-term buoyant pebbles. We provide enough media to fill the grow bed, and we recommend using all of it. A top layer of clay pebbles which remain dry is normal. Keeping the water level below the surface of the media helps reduce water loss to evaporation. In normal operation, the water should reach within a half-inch or so of the surface, especially since the porous media will wick water up above the level of the water set by the drains. As long as your plants' roots are below the surface of the media, they should have plenty of access to water.