I have a 5 gallon aquaponics tank with 1 betta and 1 mystery snail. I do weekly partial water changes and today my nitrogen was spiked way high. Immediately upon testing it became a bright purple. I did a 75% water change but curious what could've caused the spike. Once a week I give my snail a 1/2 of an algae tablet (I give him fresh vegetables every day). I put the tablet in earlier today and curious if that's what caused the spike.