Is there an optimal salinity for F8's?

[odinsfury]

I've been keeping my figure 8 puffer's salinity at 1.003 but it seems a lot of people are saying 1.005 is the best.

[Pufferpunk]

1.003-1.005.

[RTR]

A huge +1 to Pufferpunk's comment above. I have tried to differentiated between the two and cannot do so.

For optimum health and lifespan, the carbonate hardness must also be monitored and supplemented if required for stability. wide fluctuations in carbonate hardness are not beneficial. Stability here is as important as the salinity, possibly even more so.

HTH

[odinsfury]

I'm using an aragonite sand substrate. Is this enough to maintain a stable carbonate hardness, or should i test for it?

[Pufferpunk]

Test & add more salt, if necessary.

[RTR]

Again +1. Don't guess, test.

All of my display low-end BW tanks have been either refugium or RFUG with CaribSea aragonites to ensure adequate carbonate hardness. But I have to confess to being a bit compulsive. I had rather over-plan than have to go back and rebuild later - all my set-ups are set for 10 or more years of operation. I am very lazy really - doing it right once is so much easier than having to re-do every couple of years.

[odinsfury]

What is a desirable KH?

[RTR]

Stability may be more important than any particular value. The numerical value for KH will be affected by the water's whole profile, but whatever gives you a stable pH between 7.5 and 8.5 will work for you F-8.

Do remember that commercial buffers tend to do nothing at all for the KH, as they tend to affect the pH without affecting the KH at all. regardless of what the LFS or chain store may say, those do nothing at all for the important water parameters. I never use any commercial buffers. Fish don't really read pH, they read particular dissolved minerals, and carbonates/bicarbonates are critical for many of them.

Also remember to adjust the KH in your mixing or aging buckets or tanks, never in the tank with the fish. Bicarbonates tend to be quite fast-dissolving and can cause hazardous osmotic shock or death in sensitive critters. I never do such adjustments in occupied tanks, only in the make-up or water change water.

HTH

[RTR]

Adendum to above note: Never forget that carbonates/bicarbonates are used up in all aerobic nitrification, which still occurs in FOWLR tanks (just to a lesser extent than in purely bacterially bio-filtered tanks). That means that tank water loses carbonate/bicarbonates constantly, even in FOWLR tanks, just not as strongly.

[odinsfury]

Thanks for all the information. I've always tested for ammonia, nitrites, nitrates, and pH. kh was not included in my test kit so I'll have to pick one up today. My pH has been at 8.0 since I put him in his 20 long with the aragonite sand under your advice. He's alone in there, I do at least a 50% water change every week, sometimes sooner. I feed him ramshorn snails and bloodworms soaked in vitamin water. If there is anything else I have missed besides the KH test please feel free to let me know.

[RTR]

No, your handling sounds just right. Your water sounds ideal due to it's stability at pH 8. Later the fish will have a larger bioload as it matures, but you should be able to keep up with it easily.

Every few years you will need to add a bit more aragonite. Some of the sand does dissolve in keeping the carbonate hardness up. But your water is better than mine for using with these fish - I have to boost the carbonate/bicarbonate before I use the water.

[odinsfury]

I'm glad to hear that. I did my first kh test today. It took 13 drops to change the water from blue to lime green.

[RTR]

Your water definitely will be more stable than mine! That is a very good thing.

I do admit it sounds a bit odd, but these fish which can in the wild move freely between quite different water conditions, while in captivity seem to do best with the tightest stability we can manage. It does give us paradoxes to think about.

[odinsfury]

I have some new concerns and I'm not sure if this is the best place to share them, but I think you'll see them here.

We had to move somewhat unexpectedly. Our landlord decided to sell the house and we didn't want to buy it. So, now that we've moved and took great care to transfer my puffers tank and his ramshorn snail breeding tank I'm concerned about my ramshorn population. The tanks have both been set up for 2 weeks. I tested the KH from the freshwater breeding tank and it took 28 drops to change the color from blue to yellow. From my limited understanding of carbonate hardness a high level does not signify a high level of calcium necessarily, which is something ramshorn snails need. Several of the egg sacs that were on the glass seemed to have hatched but my snail population is dwindling. They're eating all of the spinach I put out for them within 2 days. I really don't have anymore small snails to feed him at this point. Am I worrying for no reason? Should I just keep feeding them and hope they start breeding again?

[Pufferpunk]

I'm not sure if this is the best place to share them

Yes, please start a new thread on this in the FW Tank section.