Those crystal tetras are awesome! I noticed wet spot had some up for sale recently as well as an ďornate crystal tetraĒ which i think is also referred to as a hummingbird tetra... itís part of a complex of dwarf tetras from Peru that are really colorful and def on my list for the 20 gal office tank rescape coming soon!
Thanks to all for explaining your water change routines for your rare tetras! I was surprised to see such large volumes of water being changed at once. When I start approaching 50% in a large tank, I get freaked out over the rapid change in parameters it could cause.
Itís too much water to go with straight rodi water without at least some remineralization but if I do remineralize or cut with tap water, it ends up being so close in ec/tds to the water Iím removing that It negates the main reason I change water in the first place! (To remove dissolved solids/reset the ec back to my base range of 225-250 microsiemens).
Iím curious to see the parameters of the replacement water when youíre changing out 75% at once. Is it pure rodi, a mix of rodi/tap, do you remineralize to predetermined ec/tds, or do you base the water quality on some other metric? Also curious to hear how your plants respond to such large changes.
Until recently Iíve had a very light bioload in the 120 but Iím now up to about 60 fish (not counting clean up crew). Iím anticipating that Iíll need to increase my water changes from 30% a week to closer to 50% but I hate wasting water and I really hate disposing of nutrient laden water back in to the watershed, so Iím wondering that I can lower the % changed by using pure unmineralized rodi to basically just dillute the minerals and nutrients already in the system back to my base level.
My only concern with this method would be the eventual accumulation of one or more elements that isnít being utilized as quickly as others or depletion of a given element like calcium or magnesium over time. Love to hear how you guys pull off these large wcís without stressing the tanks inhabitants!
Experience: worked in fishroom of Eddies Aquarium in Albany all through college, 20 years of keeping reef tanks, planted tanks, and dart frog vivariums.
Current/in-progress tanks: 20 gallon hi tech tank in office, 120 gallon nature/tetra aquarium at home.
Philosophy: work with what youíve got, and make choices based on the conditions that easiest for you to maintain over time.