Closed water system

[LoGeek]

I'm "new" to discus for the second time in my life now. As opposed to the first time I've now understood the importance of changing a lot of water. My goal is not to grow big show fish, but to learn more about discus while keeping them healthy. I'm in the process of installing a water changing system in order to make frequent large water changes take less effort. This got me thinking about the massive amounts of water I will be draining every year. I don't even want to do the math with the cost per gallon of water where I live!

I lack deeper knowledge in water chemistry, but just out of curiosity I wonder what it takes to build a closed water system? I mean a large local mechanical and biological filtration to which tank water is drained, filtered and in time ready for reuse. Maybe partly replaced with new water or all of it replaced a couple of times a year.

Is it possible within realistic boundaries? What steps would be needed? How big a water volume would be required? How large space would it take?

Maybe a stupid question, but I tried to search the forum and google and did not find any answers.

Happy christmas from Sweden everyone!

[LoGeek]

If this thread should have been in the DIY-section, then feel free to move it...

[Akili]

If this thread should have been in the DIY-section, then feel free to move it...

Water Works is appropriate for this thread in my opinion.

[Neptune]

I suppose you could run it back through an RO unit.
But even then RO's produce a lot of waste water, 4:1 for a typical unit, so not sure how much you would actually come out ahead.

[DJW]

I wish you luck... but the cost of removing nitrate and sterilizing it would probably surpass the cost of fresh water. I have an unlimited supply of free water that just needs particulate filtration and sterilization, no nitrate to worry about, and even that is a big expense to set up. RO is the only practical way I know of to remove nitrate on a large scale... and there will be waste water.

Alexander Piwowarski re-circulates water through a highly efficient RO filter.

http://www.diskuszucht-piwowarski.de/technikengl.htm

[LoGeek]

You're probably right Dan. I do not intent to actually attempt a recirculating system, just curious about what would be needed.

Lets say you had a huge refugium that you drained water to. What water quality could it produce? Would bacteria build up and cause problems?

[Hart24601]

I have been discussing refugiums in another thread and on monsterfiskkeepers. It's very possible that a large refugium could work for this purpose. The export much balance the import so there is a huge difference between keeping a reasonable bioload of 1 adult fish per 10 gallons and growing out 50 babies feeding them beefheart 3-6 times a day. A properly managed refugium should control bacteria well. Here is the post I put on MFK:

The best plant and setup I have used is water lettuce. You just need enough light for it, but you can see it grow daily and in a refugium style setup you can export (aka scoop out) a lot each week. Remember the majority of nitrogenous waste removed will be in the plant's tissue so if your tank produces 1ppm nitrate a day then you need (almost) enough growth to "lock" those compounds and export as desired.

Few papers here, 1st is looking at Water Hyacinth, Water Lettuce and Vetiver Grass as exports. The grass gets a bit too big for most. I have used hyacinth and prefer managing WL. WL also has lower N and P requirements so it will grow better once those levels start getting low. Just have to use a lot of light IMO but it grows insanely fast.

http://article.sapub.org/10.5923.j.re.20120205.04.html

Here are a couple other papers using water lettuce, these are recently published, seems to be getting more attention.

http://www.isaet.org/images/extraimages/P315027.pdf

https://www.deepdyve.com/lp/elsevie....ing-NJwK6JcE0v

http://www.iosrjournals.org/iosr-jmc...3020198101.pdf

[Hart24601]

Here is a quote from one about growth of water lettuce:

"Fonkou et al.[21] stated that lettuce doubles its biomass in just over 5 days; triples it in 10 days, quadruples in 20 days and has its original biomass multiplied by a factor of 9 in less than one month. This evolution indicates that 25 days is the maximum period to allow the plant in the system."

From another article:

"During the 10-day retention period, the sand- based constructed wetland set up with Water Lettuce had improved the wastewater quality significantly as it had reduced 75.66% of Turbidity, BOD5 by 83.43%, NO-3 by over 50%, 90% of SO-4 , 46.2% of Cl- and Conductivity by 46.2% and Dissolve Oxygen by 58%."

Here is the table and pics from the above article, note nitrate effluent started at 20ppm and 1 day reduced to 10ppm and by day 9 was 0!

wc.JPG

[jawfish]

The Gemans have been experimenting with Resins for several years now... Its based on a Nitrate absorbing resin and then run a Kati-Ani to desalinate the water from the reject of the nitrate resins.
have a look http://www.diskus-scheune-bilshausen.de/awab-system/

They have a forum www.diskus-connection.de

It has tickle my curiosity and I've been looking at setting a small experiment section of my Discus Room to try it out. It's not a start and forget system, it does require constant monitoring.

It's complicated, expensive and high maintenance... The resins and their reactors are expensive and do require to be recharged on a regular basis. A good UV and large biological filter is required, plus because you are running at low hardness you should have a way to increase the hardness when the water PH falls below a certain level Ideally you would want a very good controller to help you run the system. You should do some small water changes.

I've been studying the concept for over a year and I have a pretty good idea how I would do it, but the cost right now is not justifiable to me... My discus budget is going to my building of my Discus Room :-)

Cheers,

Fred

[LoGeek]

Here is a quote from one about growth of water lettuce:

"Fonkou et al.[21] stated that lettuce doubles its biomass in just over 5 days; triples it in 10 days, quadruples in 20 days and has its original biomass multiplied by a factor of 9 in less than one month. This evolution indicates that 25 days is the maximum period to allow the plant in the system."

From another article:

"During the 10-day retention period, the sand- based constructed wetland set up with Water Lettuce had improved the wastewater quality significantly as it had reduced 75.66% of Turbidity, BOD5 by 83.43%, NO-3 by over 50%, 90% of SO-4 , 46.2% of Cl- and Conductivity by 46.2% and Dissolve Oxygen by 58%."

Here is the table and pics from the above article, note nitrate effluent started at 20ppm and 1 day reduced to 10ppm and by day 9 was 0!

wc.JPG

Wow, thanks for great replies!

I found the report your data was copied from. If I interpret it correct the test basin was about 1 m2 and they treated 75 liters of water.

Is there any simple estimation of lets say how many grams of water lettuce that needs to grow to bind 1ppm of nitrate? I would like to transfer your very interesting links to figures that are easy to grasp. Idealy ending up with something like gallons of refugium per adult discus.

[Filip]

Above mentioned Plants and Resins address only the Nh3, No2 and No3 in the water .
We still have to figure out way how to keep bacterial , viral, parasitic and overall pathogen count under controll.
Oversized Top quality UV will surely help a lot handling pathogens in the water but I doubt if it will be enough to completely rely on it and completely avoid further WCs.

Mr.Dan / DJW gave us a pretty good and trustworthy link where we can see all the gadgets and tech involved and needed for this purpose , so it would be very incomplete if we are about to rely completely on plants and their nitrate uptake when adressing this matter.

Just my 2 cents on this subject .

[LoGeek]

And how quickly would bacteria, virus and parasites build up to problematic levels? All the water in the tank and refugium could be changed once in a while, but if they build up quickly than it causes problems...

[Filip]

And how quickly would bacteria, virus and parasites build up to problematic levels? All the water in the tank and refugium could be changed once in a while, but if they build up quickly than it causes problems...

Performing bacterial plate count and other similar microbiological examinations are impossible for us hobbyist to do.
In lack of extensive scientific knowledge about complex biology/ chemistry of our tank water , experience from the veterans is the safest bet to lean on IMO .

[LoGeek]

Yes for sure. I was just looking for a rule of thumb. Do they build up in 2 days or 2 weeks in a normally stocked discus tank?

[Filip]

Yes for sure. I was just looking for a rule of thumb. Do they build up in 2 days or 2 weeks in a normally stocked discus tank?

Well Logeek , taken from the advices for daily WCs experienced discus keepers repeat over and over again I would presume that they build up in 2 days , rather then weeks .
But this is just my LoGeek-al and intuitive opinion , because neither of us here has scientific proof and measures about those processes.