Stainless toxic for tropical setup?

[bendog]

G'day,

I am in the process of building a new 8' x 2.5' x 1.5' that will be a Fresh Water Tropical planted set up.
The Jarrah cabinet base is near finnished and the tank is on. (pic below)
I am in the process of seting up all the hardware and plumbing.
This is where I fear I may have stuffed up.

I have built my own canister filters from 316L stainless cylinders.
The reason I went down this road is I wanted larger volume filters with a backflush facility for easier maintenance.

I have recently read in an older fishkeeping book that all metals including stainless are a bad idea for aquariums.( after I finnished the filters:eek:)
Is this the case for all fish keeping or just marine setups?
I have searched google and a number of web sites but the info seems a bit vague/ contradicting with respect to stainless steel aquarium components.
The LFS said nothing when I was speaking to them about my stainless filtration plans.

Does anyone here have any thoughts on this?

[Woodsy]

Beautiful tank there mate. The subject is not one that pops up very often, and even then, like you said, it's mainly in regards to marine aquariums. In my experience, it has a lot to do with the grade of stainless you are using. Poor grades will "stain" and release metal oxides into your water. That, I'm afraid, is about as far as my knowledge on the subject stretches. However, I wouldn't be surprised if it does strange things to water, acting as a catalyst for reactions that wouldn't normally take place. Depending on how much you spent making them, it might pay to just figure it out for yourself if nobody can give you more useful information. In this case, I wouldn't be putting valuable fish in there until it's tried and tested though. Good luck with it, I hope you keep us updated ;)

[bendog]

Thanks for the reply woodsy,
I was told 316L (stirling metals) will not stain in fresh water.
Reliable information is a bit hard to find regarding stainless in aquariums.
I found plenty of stainless aquarium heaters on the web for both fresh and salt use.
Might have to learn this one the hard way. I'd rather not though.
Any one else got any experience whith stainless?

[GoGuppy]

G'day,
I have recently read in an older fishkeeping book that all metals including stainless are a bad idea for aquariums.( after I finnished the filters:eek:)
Is this the case for all fish keeping or just marine setups?
I have searched google and a number of web sites but the info seems a bit vague/ contradicting with respect to stainless steel aquarium components.
The LFS said nothing when I was speaking to them about my stainless filtration plans. Does anyone here have any thoughts on this?

G'day bendog

Hey that's a great looking tank there, are you going to keep cichlids?

As Woodsy said there are many grades of stainless steel. :confused:...Each grade of stainless is formulated for a specific type of application.

Some grades, such as 3CR12, do rust to a certain degree but then no further. These are relatively cheap and used extensively in construction applications.

Other stainless steels excell at very high temperature applications (eg Grade 310) and some grades excell at resisting extremely corrosive environments (eg Grade 316L), but both of these grades are expensive. A commonly used grade (304) is a compromise between cost and reasonable performance.

Given that some grades are used in surgical applications, and also that some aquarium heaters are sold with a stainless steel sheath, I would suspect as long as you use a suitable grade of stainless, it should be OK or even excellent...:)

I note you used grade 316L for your filter which in principle is an excellent choice. The "L" in the grade stands for low "carbon" in the alloy mix, which is exactly what you want in this type of application.

One word of warning though (and this is a common mistake, as I've just witnessed during an audit of a stainless steel installation at a Defence facility in the past few weeks): Do not touch "white" steel (that is the european term for stainless steel) with "black" steel (that is carbon steel) as the stainless steel will become contaminated and rust, even 316L. What this means is, in the manufacturing and assembling processes DO NOT USE carbon steel tools, or tools that have been used on black steel AT ANY TIME on the filter. You need to use new cutting/grinding wheels, stainless steel wire brushes, etc.

Let me know if you need more info on the above, because this is getting a bit technical, and I may be able to help.

Cheers

[wombat1100]

I wanna see the canister filters you made!
got any pics?
what if you were to powder coat them, therefore eliminating the contact with the stainless and the water?
Dazz

[bendog]

Thanks for the info goguppy,
I am planning to slowly begin with some Guppies, neon tetras, gouramis and see how it all goes. Then maybe some plants.

I did segregate everything during the filter fabrication. I am fairly confident that there will be no contamination of the shiny stuff.
All new cutting / flap disks for the job, wool carpet mat on the work bench.

Here's some pic's for ya wombat.

Bottom hose is the back flush exit pipe from the base of the filter to a bigger pump and out to the garden. Above that is the middle inlet flowing up inside the filter through the layers of coarse and medium filter media before exiting out the top hose up to the top of the aquarium and trickle trough a fine filter pad.

I ended up making two filters and have two seperate filtration systems for some reliability in the event of pump failure or stuff up.
I am almost finnished and ready for water.
I reckon I might give it a go. Run it for a while with water only and get it tested?
Then maybe go through the usual cycling process and slowly stock it and see what happens.
Fingers crossed.

[Woodsy]

The only metals LFS's really test for are on a regular basis, are calcium, magnesium, strontium, iron, and copper. Otherwise, you might have to get it run through a gc/ms for a more comprehensive break down. Much easier (and probably cheaper) just to try the filter out and see whether it works, and just refrain for stocking with expensive things in the meantime.

[GoGuppy]

.....Here's some pic's for ya wombat.....

Pictures??:confused:??

I agree, give it a go and see how the filter runs. I would keep a look out for any signs of any rusty marks developing though, over a period of time, but there are ways of treating this should this occur.

Cheers

[GoGuppy]

G'day,

I have built my own canister filters from 316L stainless cylinders.
The reason I went down this road is I wanted larger volume filters with a backflush facility for easier maintenance.
........
Does anyone here have any thoughts on this?

Hey bendog

Have a look at this thread that may be of interest to you, as it discusses a back flush system I had on my Fluval filter at the time.:)

http://www.thefishtank.com.au/forums/showthread.php?t=82&highlight=biomax

Cheers

[wombat1100]

OMG what a filter! how big is that pump???? u will have a whirlpool in there if you arent carefull!!!!
any thoughts on the powdercoating?

[GoGuppy]

Hey bendog, you don't do things by halves do you? I think your local water supply authority might come and rent some filter capacity off you..:D..

Woodsy, will the powder coating stick properly to the stainless steel? Wouldn't want it flaking off....and is this something you can apply in the home workshed? :confused:

Cheers

[Woodsy]

Couldn't honestly answer that for you mate. It sticks to computer cases just fine, and you can do it yourself in the shed, but I don't think I'd trust it to hold up under water and pressure flow. Stainless isn't a real good surface for sticking things too, and I would most definitely expect any paint or powder coat to eventually flake off. I'm no expert though, Dazz might know more.

[bendog]

G'day all,

Thanks for the replies and the link, good read.
Prety much what I am trying to do.
Its a shame the Aqarium filter design engineers don't talk to their industrial collegues.

The middle pump (big green one) is a davey rebadge stainless bore pump and will be used soley for the back flush of the filters. It has to pump up 3m of head and still have sufficient velocity to remove the crud from the filter media.
There is a smaller Eheim pump tucked away in each end for the normal filter duties. Its a big tank. There will hopefully be alot of happy and busy fish eating and pooping in there.

My plan is once the tank is established to do 10% part water change using the tank water for backflush each week. I will have to inspect the guts of the filters fairly often initially to see how well it works.
I am hoping that the filters will only need maintenance and new media once a year, 1 filter job every six months leaving the other filter full of bacteria to do its thing. Have to wait and see on that one. It might be a failure yet.

I am prone to a bit of over kill bill every now n then. It has mostly paid off in the past having a bit extra.
I can choke the flow rate back with the ball valves if the fish get too dizzy:p


I had a chat to a work mate today regarding painting the inside of stainless.
It can be done but would be a major PIA to do. (prep, prime and top coat)
Stainless is a bugger to paint.
It will be difficult (for me) to eveny coat inside such a small diameter Cylinder(370mm dia) with the spray gun.
And there are some parts that are not accessable (in the tubes) which will can't be coated. I'll see how it goes as is I reckon.

I am planning to have water in it over the weekend.
I can post when there is more progress next week if your interested?
Thanks for the input.;)

Ben

[wombat1100]

Definitely keep us informed mate, its a ripper idea and I'm almost sure it will be OK , but time will tell, as previously suggested, get some cheap fish to try it out on first, and see how you go. look forward to progress reports and pics
Dazz

[joz]

Ecellent work there bendog,it looks like that filtration will far exceed whatever you have in the tank.
I wish I could help with any stainless info but I have no idea at all,sorry.

[GoGuppy]

Give it a go, bendog, and see how you go.. :) I for one, think you will have no problems with using stainless steel..

When you next open up the filter though, i would suggest you give the internals a good clean with old clean rags, let it dry and under good light look for any tiny pits of corrosion, or little scratches that show up and are rust coloured. As I said, if you do find that, the good news is that it is reasonably easy to fix by means of passivation.
In any case, by the looks of the filters, you've got plenty of wall thickness, so not likely to pinhole quickly..:).

And yes please... do keep us up to date on how things are progressing!!
Cheers

[bendog]

Two week update.

Filled the tank up and fired it all up.
Couple of minor water drips, nothing too major.
Had to throttle back the pumps a bit. Water flow were a bit too strong.

I gave it a few days running to settle and play with the backflush setup. Worked well.
I added 20 mollies on the 3rd day and so far so good.
I lost two mollies down the filter inlet. Had to make up a more protective inlet. Learnt that one the hard way.

Amonia is slowly starting to rise to .25 (day 10) No nitrite yet. Temps at 26 degc. Ph is stable at 7.6. Fish seem to be ok.

After 9 days of fish in the tank I have done the first proper filter backflush.
I could not be happier with the speed and easy way to clean the filters.
It took less than 5 minutes to flush both filters using about 25% of the tank water. I was surprised at the amount of crud that came out.
The stainless bore pump was big enough to get a good velocity of water exiting the filters.
The water exiting the filters during the flush ran clear after about 30 seconds. I am so glad it works, better than I expected.
Jury is still out on the stainless with respect to contamination of the tank water. Time will tell on that one. so far so good. I have dropped a spare 316ss fitting in the back corner of the tank so i can monitor it for corrosion on a regular basis.
As for the backflush, it works perfectly. Cleaning two canister filters, 60 litres each, in less than five minutes, without getting my hands wet is great.

Cheers, Ben

[GoGuppy]

Looking good mate. I was wondering what kind of media are you using in the filter? Do you use separate baskets for different types of media?

I'll have to think about hooking up a back flush system again, it does save time.
Cheers

[bendog]

I welded a base (cris cross 6mm round) inside the filters about 200mm up from the bottom to stop the media from falling down.
I have used two different filter media in each cyclinder. I purchased it in 1200 x 1200 40mm thick sheets from the LFS. Not sure what it is called but it looks like a big plastic crazy string pad. I cut the circles out to fit snug inside the cylinder and layered it up just below the outlet pipe at the top.

4 layers of the coarser green pad then 4 layers of the finer blue pad.
I was going to put a basket up the top of the tank with some fine filter wool in it to catch the fine stuff but I have found that it is not required at this stage.

When I first filled the tank and put the rocks in it was a bit murky. Within two hours or so of the filters running it was crystal clear.
I think the combination of the void at the base of the filter with the water swirling around like a cyclone inside before it drifts up throught the 8 layers of media is enough to catch even the fine particles before the water gets to the top exit pipe.
I am stoked with the results at this stage. Early days yet though.
See how it goes when there are another fifty odd fish in there messing the place up.
I will tear one of the filters down in 3-4 weeks time to see how it looks inside I will take some photos of the guts of it and post it up here so every one can see whats inside. Like any thing there is probably still room for improvment. The more ideas the better.
Keep 'em coming.

[GoGuppy]

Thanks for that bendog. Always interesting to hear what other people do with their filters. I have also long time ago done away with using filter flos in my filter, as I too found that after a while, when things have settled down in the tank, I get crystal clear water without using floss.

I may use it very occasionly for a specific purpose, such as recently when I replanted my tank the water was very murky and to please the fish I put some floss in as a polisher in the final stage of filter media. Only left it in for a few days the removed it again.

A bit like using activated carbon actually, use it for a specific purpose (usually to remove medication from tank water) then remove it.

Look forward to seeing the photos of the filter media when you next open it up again.

Cheers

[wombat1100]

Very informative there Bendog, good to hear progress is positive, keep an eye on it and keep the reports and pics coming, you might have to build a few more for the members if they work that well;) he he