Fastest Way To Convert From Fw To Bw?

[johnnyr]

Hi all,

I've decided to take the plunge, and try to start up a brackish tank. I have a very mature 20 gallon now, and need to know what the quickest way to convert from FW to BW would be. I really don't want to re-cycle my tank, since that takes weeks, and I would like to get my brackish fish in the tank by next week. (The store is holding thier last two pair of moray eels for me)

Any suggestions? I've used bio-spira with success in the past, but I'm not sure if it would work with brackish. They do have a SW version as well.

 

[nmonks]

Here's your thing: you can take a freshwater filter to 1.005, and expect everything to remain working normally. But once you go above that, the filter somehow adapts to the higher salinity, and has to become re-matured. I'm not sure what the microbiology is. So if it was me in this situation, I'd adapt the tank to SG 1.005 in stages over the next few days. Make sure the nitrites are good, then add your brackish water fish. Over the next few months, raise the SG a tiny amount with each water change, and monitor the nitrites. With luck, the filter will adapt in pace with the changes.

Anyway, your morays want SG ~1.010 over the long term. Which species are they? Assuming they're Gymnothorax tile, you'll probably be able to keep them for weeks, maybe months, at SG 1.005, but you will need saltier water than that over the long term. However, 20 gallons (especially US gallons) is far too little for moray eels. These are very active fish that can get to 60 cm long. While I applaud your desire to keep them as a group, they will need some space if they're to settle in nicely. I'd be thinking about a tank 50-100% larger than what you have in mind, at the very least.

Cheers,

Neale

 

[johnnyr]

Here's your thing: you can take a freshwater filter to 1.005, and expect everything to remain working normally. But once you go above that, the filter somehow adapts to the higher salinity, and has to become re-matured. I'm not sure what the microbiology is. So if it was me in this situation, I'd adapt the tank to SG 1.005 in stages over the next few days. Make sure the nitrites are good, then add your brackish water fish. Over the next few months, raise the SG a tiny amount with each water change, and monitor the nitrites. With luck, the filter will adapt in pace with the changes.

Anyway, your morays want SG ~1.010 over the long term. Which species are they? Assuming they're Gymnothorax tile, you'll probably be able to keep them for weeks, maybe months, at SG 1.005, but you will need saltier water than that over the long term. However, 20 gallons (especially US gallons) is far too little for moray eels. These are very active fish that can get to 60 cm long. While I applaud your desire to keep them as a group, they will need some space if they're to settle in nicely. I'd be thinking about a tank 50-100% larger than what you have in mind, at the very least.

Cheers,

Neale

Really? Thats dissapointing. I was told these particular eels would not get much larger then they already are (about 8inch). But I refuse to subject any fish (inlcuding eels) to living in sub-par conditions.

Sigh....well if I can't have eels, I guess i'll go back to my original plan, which was putting in a pair of german blue rams, some MGS snails (to stir up the sand) , and perhaps (if they don't get eaten) some bamboo shrimp in the 20 gallon and calling it a day. You seem very knowlegable, what do you think of my second plan?

Also, do you know if the rams will exhibit the digging behavior (putting sand in thier mouths and spitting it out) This is one of my favorite things to watch a cichlid do.

 

[Dave Legacy]

Let's talk Bio-spira and it's use with in brackish conditions!

I was inpatient and used it to cycle my very first tank which happened to be my 40G Archer tank @ 1.005SG. I used (and properly transported) a 30G pouch of Freshwater Bio-spira in about 25G of water with a bio-load of 4 juvenille T. jaculatrix. The first pouch bombed so badly that within an hour my NH3 levels were above 8.0ppm, where they remained for 3 days due to some poor advice, before I had to vigirously attack the tank with PWCs. I believe that a lot of the problem had to do with the fact that the freshwater strand of bacteria couldn't survive the salt content and most of it, if not all of it, perished upon contact.

Days later, with only slight results, I followed up with a dose of a 30G pouch of Marine Bio-spira. This seemed to take and accellerated my cycle to complete in approximately 2 weeks. However, not without the use of massive water changing. As a consequence to my inpatients I was forced to change 50+% of my water every 4-5 hours for 5 days straight, followed by bi-daily, daily, bi-weekly, and finally completed. The process started to move pretty quickly once the ball got rolling, but the first week was murder. Anyone else know what it feels like to wake up at 3am to do a PWC, sometimes twice a night?

I would seriously hesitate on using it again. Even in perfect conditions, in full fresh or marine, I doubt Bio-spira would complete a cycle in anything less than 48hrs to a week. My suggestion, which I also have experience with, would be to obtain some seeded bio-media from a local that has an established brackish tank. You could even get some seeded marine bio-media and bring it down to a slightly lower SG for some high-range brackish fish. Anyway, the seeded media will drastically jump start your cycle and will continue to cycle as long as you can provide it with a source of NH3. Dosed the tank daily with NH3 to a level of 2.0ppm w/seeded media and completed a cycle in 7 days.

My NH3 source, urine... straight from the tap.