Discus in my future?
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If you can skip the water softener, that will be fine for the plants. The discus also will grow well with the calcium and magnesium that the water contains. Neither the plants nor the fish need the sodium that the water softener is adding as it strips out calcium and magnesium. The sodium in the water is perhaps part of the reason the pet store said low water changes would be better.
However, with 6 or 7 fish in 70 gallons you are at the limit of the tank capacity and you will need very large water changes to keep the fish healthy. Many people who keep discus in planted tanks report that they need to either stock lightly or keep up bigger water changes. Because bacteria problems are more of an issue at the higher temps that discus require, and in alkaline water you miss the antibacterial effects of acid, you will need to be more concerned about water changes to maintain water quality than people who have softer, more acid water.
My reading has suggested that there is a fish-day/gal ratio of 0.6 that most successful discus planted tanks have. Multiply the number of fish by the days between water changes and divide by the fraction of water change (that is 0.5 for 50% or 0.2 for 20%) and by the number of gallons in the tank.
So, 6 fish getting 50% every 7 days in a 70 gallon tank is (6 x 7)/(.5 x 70) = 1.2 this is about twice as high as the safe ratio of 0.6 that I calculated from the posts I've read. To maintain these fish, you will need to be very careful to siphon all wastes daily, being sure that all food is consumed and not left to drift into the plants to decay. Even so, I'd expect some health issues from time to time.
It would be better to increase the water changes to either 75%/wk for a ratio of 0.8 or do two 50% changes a week for a ratio of 0.6 which would be recommended. Or keep less fish, or a bigger tank.
If you can skip the water softener, that will be fine for the plants. The discus also will grow well with the calcium and magnesium that the water contains. Neither the plants nor the fish need the sodium that the water softener is adding as it strips out calcium and magnesium. The sodium in the water is perhaps part of the reason the pet store said low water changes would be better.
However, with 6 or 7 fish in 70 gallons you are at the limit of the tank capacity and you will need very large water changes to keep the fish healthy. Many people who keep discus in planted tanks report that they need to either stock lightly or keep up bigger water changes. Because bacteria problems are more of an issue at the higher temps that discus require, and in alkaline water you miss the antibacterial effects of acid, you will need to be more concerned about water changes to maintain water quality than people who have softer, more acid water.
My reading has suggested that there is a fish-day/gal ratio of 0.6 that most successful discus planted tanks have. Multiply the number of fish by the days between water changes and divide by the fraction of water change (that is 0.5 for 50% or 0.2 for 20%) and by the number of gallons in the tank.
So, 6 fish getting 50% every 7 days in a 70 gallon tank is (6 x 7)/(.5 x 70) = 1.2 this is about twice as high as the safe ratio of 0.6 that I calculated from the posts I've read. To maintain these fish, you will need to be very careful to siphon all wastes daily, being sure that all food is consumed and not left to drift into the plants to decay. Even so, I'd expect some health issues from time to time.
It would be better to increase the water changes to either 75%/wk for a ratio of 0.8 or do two 50% changes a week for a ratio of 0.6 which would be recommended. Or keep less fish, or a bigger tank.
I'm still trying to find a tap that skips the softener. I'm not sure any one does, either that or my test readings are not good. I'm going to get a new test kit (the last was a bit old probably).
Any change in your advice if I can't get around the softener.
Your formula for the changes was very helpful.
Any change in your advice if I can't get around the softener.
Your formula for the changes was very helpful.
work in progress
That formula is a work in progress, I'm still collecting data and examining the extreme values I see. But, it seems to be a good place to begin, and after you get to know your fish and your water you can vary it and observe the fish for effects.
I started with 23 1" babies in a barebottom 20 gallon tank doing 60% water changes plus siphoning 2x/day and that is a ratio of 1.9, later I moved them to a 60 gallons and did 25% water chagnes daily, siphoning 2x/day so that ratio was 1.5 when they were between 1 1/2" and 3". Now, at 3-4" I have increased the water changes to 50% so the ratio is 0.76. I suspect that this month I will need to get rid of some fish.
I don't really have any experience with water softeners. I'd have to defer to any of several folks who have more knowledge on that. Just remember that the water may be "soft" for making soap bubbles but it has a high level of dissolved salts which discus don't care too much for. So, it is not soft like rain water is soft, or like Amazon water is soft.
That formula is a work in progress, I'm still collecting data and examining the extreme values I see. But, it seems to be a good place to begin, and after you get to know your fish and your water you can vary it and observe the fish for effects.
I started with 23 1" babies in a barebottom 20 gallon tank doing 60% water changes plus siphoning 2x/day and that is a ratio of 1.9, later I moved them to a 60 gallons and did 25% water chagnes daily, siphoning 2x/day so that ratio was 1.5 when they were between 1 1/2" and 3". Now, at 3-4" I have increased the water changes to 50% so the ratio is 0.76. I suspect that this month I will need to get rid of some fish.
I don't really have any experience with water softeners. I'd have to defer to any of several folks who have more knowledge on that. Just remember that the water may be "soft" for making soap bubbles but it has a high level of dissolved salts which discus don't care too much for. So, it is not soft like rain water is soft, or like Amazon water is soft.
First, most of the advice you have already been given is excellent - stay away from commerial additives in general, most cause many more issues than they solve - and especially the fact that discus, or any other blackwater fish for that matter, need special handling for breeding, not for growth, development, or maintenance. The fish are not nearly so sensitive as the egg membranes are. In high TDS (total disolved solids) water, egg membranes of these fish are effectively tanned - either the sperm cannot penetrate the toughened egg membrane, or if fertilized the fry cannot break out of the hardened egg, even with the parents' help.
For development and growth, higher TDS water does seem to help young discus a bit, so that is no biggie. Bare-bottom tanks are utilitarian. Discus are picky, many are inbred for color/form development and predictability, they do best quite warm in comparison to most tropicals - and the kicker - warmer water hold less oxygen (discus are large-bodied fish with high O2 demands), and bacteria grow much faster in warmer water. So, you want to feed a lot of high-protein food, but you cannot afford to poison the water with bacterial blooms, which could also suffocate the fish. Discus also do not like stong current, so you cannot filter these tanks to white-water rapids levels. Keeping the tank base bare, any plants present in pots, means that you can get rid of poop and uneaten food easily and well. Do it that way.
Everybody loves planted tanks. I am one of them. Guess what? Discus streams are all but plantless. Blackwater eats light. The streams are full of driftwood tangles - and the water is dark brown. That is where they come from. In captivity, they are happy to accept heavily planted tanks, and use the plants just as they do the driftwood in the wild - for security, for refuge from predators, and to avoid the main-flow current. But trying to feed and grow immature discus to full tank size (commonly larger than wild size BTW) is an exercise in futility in planted tanks - can you say algae heaven? Grow them out in utilitarian setups with a few large potted swords for company, then move the adults to a beautifully landscaped planted tank.
Okay, back to water. Salt-exchange "softeners" trade sodium (usually) ions, Na+, for calcium and magnesium ions (Ca++, Mg++). Those are the ions which make water "hard" - that is hard to produce a foam with soap, and those ions also tend to make soap scums precipitate out on clothes. Bad for the laundry. Sodium replaces those and has no bad effect on soap foam, nor does it salt out the scum. BUT (big but), sodium is plus-one (Na+), calcium and magnesium are plus-two (Ca++, Mg++). All exchanges must balance, or they do not work. This means that two Na+ ions must go into solution for every Ca++ or Mg++ pulled out. Guess what that means to the fish keeper? The TDS mentioned above, the total dissolved solids, is now higher than it was before the exchange. For blackwater fish to breed, they need very low TDS water, not very "soft" water in the laundry sense, nor very acid in the pH sense - but low TDS, which will be acid because it has all but no carbonates to balace out CO2, plus it is loaded with tannins/tannic acid which are mild to moderately strong acids. Their native water is not "soft" in the laundry sense, it is low TDS and high acid.
For planted tanks the situation is worse. High sodium blocks some calcium and magnesium plant processes. So the water is worse for planted tanks than it is for breeding discus, or at least as bad. Using a different salt, potassium chloride (KCL), rather than sodium chloride (NaCL) would be better. Plants need a good bit of potassium (the K of NPK in fertilizers), much more than sodium. It costs a bit more, but not prohibitively more - heart patients/blood pressure patients use this if they must use softeners - and it is commonly available at home stores and from water maintenance companies.
So grow the discus out in tap of whatever sort, preferably bare bottomed. Then investigate a different salt for the exchanger while you develop your planted tank for the adults. When you are ready to breed pairs, move them back to the bare-bottomed grow out tank and condition them there, with KCl-softened water mixed with RO to make low TDS water for breeding, using the CO2 from your planted tank to hold the pH down a bit (rather than add tannins).
HTH, and apologies for the long post.
For development and growth, higher TDS water does seem to help young discus a bit, so that is no biggie. Bare-bottom tanks are utilitarian. Discus are picky, many are inbred for color/form development and predictability, they do best quite warm in comparison to most tropicals - and the kicker - warmer water hold less oxygen (discus are large-bodied fish with high O2 demands), and bacteria grow much faster in warmer water. So, you want to feed a lot of high-protein food, but you cannot afford to poison the water with bacterial blooms, which could also suffocate the fish. Discus also do not like stong current, so you cannot filter these tanks to white-water rapids levels. Keeping the tank base bare, any plants present in pots, means that you can get rid of poop and uneaten food easily and well. Do it that way.
Everybody loves planted tanks. I am one of them. Guess what? Discus streams are all but plantless. Blackwater eats light. The streams are full of driftwood tangles - and the water is dark brown. That is where they come from. In captivity, they are happy to accept heavily planted tanks, and use the plants just as they do the driftwood in the wild - for security, for refuge from predators, and to avoid the main-flow current. But trying to feed and grow immature discus to full tank size (commonly larger than wild size BTW) is an exercise in futility in planted tanks - can you say algae heaven? Grow them out in utilitarian setups with a few large potted swords for company, then move the adults to a beautifully landscaped planted tank.
Okay, back to water. Salt-exchange "softeners" trade sodium (usually) ions, Na+, for calcium and magnesium ions (Ca++, Mg++). Those are the ions which make water "hard" - that is hard to produce a foam with soap, and those ions also tend to make soap scums precipitate out on clothes. Bad for the laundry. Sodium replaces those and has no bad effect on soap foam, nor does it salt out the scum. BUT (big but), sodium is plus-one (Na+), calcium and magnesium are plus-two (Ca++, Mg++). All exchanges must balance, or they do not work. This means that two Na+ ions must go into solution for every Ca++ or Mg++ pulled out. Guess what that means to the fish keeper? The TDS mentioned above, the total dissolved solids, is now higher than it was before the exchange. For blackwater fish to breed, they need very low TDS water, not very "soft" water in the laundry sense, nor very acid in the pH sense - but low TDS, which will be acid because it has all but no carbonates to balace out CO2, plus it is loaded with tannins/tannic acid which are mild to moderately strong acids. Their native water is not "soft" in the laundry sense, it is low TDS and high acid.
For planted tanks the situation is worse. High sodium blocks some calcium and magnesium plant processes. So the water is worse for planted tanks than it is for breeding discus, or at least as bad. Using a different salt, potassium chloride (KCL), rather than sodium chloride (NaCL) would be better. Plants need a good bit of potassium (the K of NPK in fertilizers), much more than sodium. It costs a bit more, but not prohibitively more - heart patients/blood pressure patients use this if they must use softeners - and it is commonly available at home stores and from water maintenance companies.
So grow the discus out in tap of whatever sort, preferably bare bottomed. Then investigate a different salt for the exchanger while you develop your planted tank for the adults. When you are ready to breed pairs, move them back to the bare-bottomed grow out tank and condition them there, with KCl-softened water mixed with RO to make low TDS water for breeding, using the CO2 from your planted tank to hold the pH down a bit (rather than add tannins).
HTH, and apologies for the long post.
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