Converting reef to freshwater...

Steve Maxwell · Jul 7, 2016

Hello,

I have a 75G reef tank that I'm thinking about converting to a freshwater tank. It's been decades since I've had a freshwater tank and was wondering how to go about converting my drilled tank reef to a freshwater tank? Should I still use the filter sock, sump, refugium from my reef tank in a freshwater set-up? Should I still use my protein skimmer? Should I still use my reactor that I'm running carbon & GFO in? Is there still a general consensus of x inches of fish per gallon? I'd probably do a community tank, but not 100% sure.

I've asked this on a couple freshwater sites and haven't gotten much info, but I'm sure there's quite a few people here on R2R who have done this. I'm still keeping my other reef tank up, just wanting to spend less $$$ and have less upkeep/maintenance on my 75G

Thanks!
--Steve

DracoKat · Jul 7, 2016

I switch a small 9 gal tank from reef to FW, but it's nothing massive like yours.

You will have to give the tank and all equipment a good thorough cleaning to get rid of any and all salt residue.

I don't see any reason why you should get rid of the sump, more water volume, the better, right? you may not be able to use the skimmer- but an ATO would be useful too if you have that. You may be able to get away with using a CO2 doser in the sump to keep it out of the DT, if you decide to go the planted route.

as for fish, 1 inch per gallon I do not follow anymore. I look at the fish personality and the sizes. Live Aquaria helps with the stocking

CodyRVA · Jul 7, 2016

I would only remove what isn't usable. Not sure if GFO would be of much use for freshwater, but to my knowledge skimmers don't work in fresh water at all.

AndyOneTwentyFive · Jul 7, 2016

Your skimmer and gfo will be unless however you may be able to use the carbon reactor. I run carbon 24/7 in my freshwater tanks but simply in a mesh bag. While the reactor may be overkill you could probably still use it. Filter socks are a must. Also, I would keep that refugium right where it is but obviously clean everything saltwater out. I keep an old piece of dead live rock in my DIY overhead sump and light the section counter to the display lights as sort of a fuge. It's got all sorts of nasty algae on it which keeps the amount of algae in my display down. Also the rock helps with biological filtration which brings me to my next point. A freshwater setup will not have biological media "built in" to the scape like a reef would. You'll want to find a chamber within the sump to dedicate to biological media. The more the better. You could use bio balls or some other media meant for aquariums or you could be a cheap skate like me and go the unconventional route with lava rock or pot scrubbies.

eatbreakfast · Jul 7, 2016

Run it freshwater with lemon juice to clean up all the equipment. Then do a big water change.

The protein skimmer won't be usable in freshwater, but gfo certainly will be, unless you are having plants.

anthonywesty · Jul 7, 2016

I was running my planted tank with sump , filter sock and carbon.

anthonywesty · Jul 7, 2016

ReeferBob · Jul 8, 2016

I'd do a complete tear-down and start over just because. The substrate (aragonite?) will make the pH too high for a FW tank so replace that. Keep the sump system lots of FW keepers are jumping on that bandwagon. Have you tried monsterfishkeepers?

BTW: A little salt left over in the tank is not a big deal

Steve Maxwell · Jul 8, 2016

Thanks for the great ideas all...keep them coming. You know, I posted on 2 different freshwater forums before posting here and I have gotten 1 response on each forum pretty much saying that they didn't know (you know there has to be some people on there who have both freshwater and reef). Just goes to show what a great website this is! @revhtree have you ever considered putting a freshwater sub-forum here on R2R? If you did that we could soon take over the entire freshwater & saltwater worlds :D!!!

NeptuneGarden · Jul 8, 2016

.. trip post

NeptuneGarden · Jul 8, 2016

Start thinking different on tank maintenance. All the equipment involved in a salt water tank is not needed on freshwater because water changes are so easy.

Set-up a system to do automatic or semi-automatic water changes. If you're good about doing 50% weekly water changes through a simple system, you dont need much filtration.
some filter socks and nice area for bio-media in the sump and weekly water changes are all that's needed.

Do you want a planted tank ? That adds a whole other level of complication.
do you want high light, high growth that requires fertilizers and Co2 injection ? or lower light, slow growth plant ? .... what plants you pick matters.
Barrreport.com is my go to source for freshwater planted aquarium expert info. Plants, water quality, fertilizers, Co2 injection, lighting, all covered in depth.

Steve Maxwell · Jul 8, 2016

Just a bit of clarification...I would like to get into a planted tank eventually, but for now to save some $$$ I think I'll not have any plant and just use some dry rock I have and some driftwood.

NeptuneGarden · Jul 8, 2016

Start with plants like anubis and java fern. Easy to grow and maintain under pretty much any condition.

I would really try and think about exactly what kind of tank you want first. You can do a really cool African cichlid tank with no plants. Very attractive and active fish, but they would quickly destroy any plants.
or if you want a tank of neon tetra and rainbows, then that requires a different plan.

For ease of maintenance I would start off with a dwarf african cichlid tank with sand bottom and lots of rocks. Less is more sometimes

Steve Maxwell · Jul 8, 2016

My kids are really wanting a school of cardinal tetras, but I know they like planted aquariums. Would it be enough to put in some easy to grow/maintain plants like anubis & java fern in a concentrated area? I have a 75g and really want to take it easy on the maintenance and $$$ if possible.

icedgxe · Jul 8, 2016

Anubias and Java fern are very easy to grow. Also take a look at cryptocoryne sp. as they are pretty hardy in my experience as well. I run all of the above with a good substrate in a low tech setup and they grow great.

Maritimer · Jul 8, 2016

I've seen cardinals in an un-planted (or barely-planted) setup as well. A few low-light plants, (Cryptocoryne, Anubias, Java fern, Java moss) lots of branchy driftwood to simulate tree roots growing in the warm, acidic waters of the Amazon, and a shoal of cardinals drifting through the branches; it can make for a pretty tank . . .

Cardinals tolerate the warm, clean, acidic water that's also the preferred habitat of discus. A few Corydoras cats on the sand, maybe some hatchetfish up at the surface. (Use a lid - hatchets are truly "flying" fish!)

Good luck!

~Bruce

ReeferBob · Jul 8, 2016

This thread has me wanting to convert my 125 gallon in-wall to freshwater. I am really getting tired of the SW maintenance!

NeptuneGarden · Jul 8, 2016

Steve Maxwell said:
My kids are really wanting a school of cardinal tetras, but I know they like planted aquariums. Would it be enough to put in some easy to grow/maintain plants like anubis & java fern in a concentrated area? I have a 75g and really want to take it easy on the maintenance and $$$ if possible.

Do a sand or gravel bottom about 1-1.5" deep. I prefer sand, it's more "bio-tope"

Driftwood with anubis, java moss, and java fern tied to it with fishing line or black sewing thread. It will take root and cover over the thread.

Stay away from stemmed plants or anything that is planted in the "soil". You'll be tempted. Don't. They're a never ending water quality and plant trimming nightmare.
You can get a very maintenance free setup and look just as nice with piles of wood covered in anubis and java. After the anubis get established they will grow small white flowers too.

Setup a system to do 50% weekly water changes as simply as possible. If you really want your tank to be happy your water change water needs aerated for 24hrs. Say a 30 gallon trash can with an air stone, heater and a transfer pump.

Houston area puts chloromine in the tap water, so make sure to test for ammonia and phosphates after you dechlorinate the tap water.

Keep the sump with a couple of filter socks for perfect mechincal scrubbing and easy change out and to help increase total water volume. Throw some carbon in there every other month or so to remove tannins. I always like Seachem Purigen too.

If your tank has an overflow you will need to put a screen in front of it to keep the cardinal tetras out of it. They will all end up down it in very short order other wise.

Most FW fish want the tank water much cooler than your used to as well. 73-75*. The tank will need a fan blowing across the top to maintain this.... or a small chiller.

AndyOneTwentyFive · Jul 9, 2016

When you say "dry rock" do you mean leftover rock from a saltwater system? If so I must warn you that type of rock will buffer the PH up around 8 just like in a saltwater tank. Cardinal tetras don't like that. African cichlids would though. However I've always been told to use smooth rock in an African cichlid tank due to the fact that they occasionally rub against the rock and may injure themselves on something like pukani.