• Hello guest! Are you an Apistogramma enthusiast? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's a great place for Apisto enthusiasts to meet online. Once you join you'll be able to post messages, upload pictures of your fish and tanks and have a great time with other Apisto enthusiasts. Sign up today!

Absolute beginner to black water tanks

Ben Rhau

Apisto Club
Messages
564
Location
San Francisco
The one thing that stood out for me in the article you linked was this bit: "Pretreating water with an RO unit can, depending on its efficiency, use quite large amounts of water with RO to wastewater ratios of up to 1:5! So if you live in areas with regular droughts, high water hardness and/or high prices on tapwater you might want to overthink this."
if you ensure adequate (but not too high) water pressure and slightly restrict the outflow, you can safely get the reject ratio down to about 1:2.5 or 1:3. Although you can technically get it down to 1:1, it's not economical to do so, and not recommended.

I live in a drought area (California) and therefore collect and reuse all of the reject water. I typically make around 6 - 7 gallons of RODI water every 3 - 5 days and use the reject water to refill the toilet.

Cheers
 

Ben Rhau

Apisto Club
Messages
564
Location
San Francisco
It's technically possible to go to 1:1, but unless you have zero hardness it will drastically reduce the life of your membrane. For example, if you run a second membrane at the waste line, you'll have an extremely high TDS going in. It's going to get awfully expensive to keep replacing that membrane. Not to mention you'll need to run higher pressure to get the water through two membranes. Anything over 75psi could compromise the housing, which will be a huge mess.

The other way to do it is to put a very low flow restrictor at the outlet, which creates similar problems.

Since I'm not wasting any of the water, I'd rather give up some efficiency to reduce the overall cost (by a lot). That's my advice, anyway.
 

anewbie

Well-Known Member
Messages
1,339
It's technically possible to go to 1:1, but unless you have zero hardness it will drastically reduce the life of your membrane. For example, if you run a second membrane at the waste line, you'll have an extremely high TDS going in. It's going to get awfully expensive to keep replacing that membrane. Not to mention you'll need to run higher pressure to get the water through two membranes. Anything over 75psi could compromise the housing, which will be a huge mess.

The other way to do it is to put a very low flow restrictor at the outlet, which creates similar problems.

Since I'm not wasting any of the water, I'd rather give up some efficiency to reduce the overall cost (by a lot). That's my advice, anyway.
They claim otherwise.... but the unit is pricey.

I thought about trying to reuse water from the aquarium (water changes) since the amount will be around 1000 gallons a week but the headache of rerouting it to the sprinkler system or similar was quite significant and I was advised to not do it.
 

Ben Rhau

Apisto Club
Messages
564
Location
San Francisco
They claim otherwise.... but the unit is pricey.
They do have a vested interest in claiming otherwise... You can read more in the reef forums, including Russ Romme, who sells RO units himself and could easily sell this arrangement. Since there's nowhere else for the ions to go besides the membrane, I don't see how you can get around the lifespan issue. But I would be happy to be proven wrong.

I thought about trying to reuse water from the aquarium (water changes) since the amount will be around 1000 gallons a week but the headache of rerouting it to the sprinkler system or similar was quite significant and I was advised to not do it.

Oh my. I can see why you'd rather optimize for reducing the ratio. I don't have nearly that much volume, 67.5 gallons total across 6 tanks. There are straightforward ways to use the reject water (washing machine, toilet) but probably not putting a very big dent in 1000 gallons.
 

anewbie

Well-Known Member
Messages
1,339
They do have a vested interest in claiming otherwise... You can read more in the reef forums, including Russ Romme, who sells RO units himself and could easily sell this arrangement. Since there's nowhere else for the ions to go besides the membrane, I don't see how you can get around the lifespan issue. But I would be happy to be proven wrong.



Oh my. I can see why you'd rather optimize for reducing the ratio. I don't have nearly that much volume, 67.5 gallons total across 6 tanks. There are straightforward ways to use the reject water (washing machine, toilet) but probably not putting a very big dent in 1000 gallons.
Setting up a pair of 450 gallon aquariums and 4 other 100 gallon aquariums. I figure if i want a community; i should give folks a bit of room to stretch out. Sizes are 10x4x22,8x4x22,4x4x20,4x4x18,6x2x18,6x2x18 (l-ft,w-ft,h-inch). Also having fewer tanks require less work to clean ;)
 

Frank Hättich

Well-Known Member
5 Year Member
Messages
556
Location
Germany
The one thing that stood out for me in the article you linked was this bit: "Pretreating water with an RO unit can, depending on its efficiency, use quite large amounts of water with RO to wastewater ratios of up to 1:5! So if you live in areas with regular droughts, high water hardness and/or high prices on tapwater you might want to overthink this."
Why don't you go for a DI-unit? I use one for many years now and I'm quite happy with it.
 

anewbie

Well-Known Member
Messages
1,339
Why don't you go for a DI-unit? I use one for many years now and I'm quite happy with it.
I'm curious is there a difference between di water and ro water ? If not why would a di unit be more efficient than a ro unit; why not just make a ro unit like a di unit ?
 

Frank Hättich

Well-Known Member
5 Year Member
Messages
556
Location
Germany
@MacZ I use this mixed bet resin: https://www.purolite.com/product-pdf/MB400.pdf
It removes "everything", my tap water has an EC of about 700uS/cm and with fresh resin the DI water is <5uS/cm.

@anewbie a DI-unit is more effiecient than an RO one in the sense that you have no waste water at all (but waste resin instead). This was the main reason for me to use DI instead of RO,, because I have no water outlet in or near my fishroom.
 

MacZ

Well-Known Member
Messages
2,904
Location
Germany
@MacZ I use this mixed bet resin: https://www.purolite.com/product-pdf/MB400.pdf
It removes "everything", my tap water has an EC of about 700uS/cm and with fresh resin the DI water is <5uS/cm.
Ah, I see. Each system has its pros and cons. I get pretty much the same result, as I have an EC in the tap of only about 200µS/cm and good pressure on the tap. The waste ratio is close to 1:1.
What are the upkeep costs? And how big of a volume can you treat before you have to change the resin?
 

Frank Hättich

Well-Known Member
5 Year Member
Messages
556
Location
Germany
I can produce 220 liter DI-water with 2,5 liter resin. The price of 25 liter resin is about 130 Euro, i.e. 220 liter DI-water cost 13 Euro. Other than the resin there are no other running costs.
 

MacZ

Well-Known Member
Messages
2,904
Location
Germany
Even though I have a bad conscience for the water waste, RO has the better bang for the price in my situation. Even if I replace the membrane once per year, DI would cost me 50 bucks more per year than RO. Schade!
 

Ben Rhau

Apisto Club
Messages
564
Location
San Francisco
@MacZ This is what @Joshaeus was doing before he got an RO unit. He shook up the water in a 2 liter bottle with DI resin and then strained it. He also reused the water from his water changes this way. Very water efficient, but does not scale easily. And not cheaper than RO.

@Frank Hättich since you don’t have a water outlet, are you using a pump to circulate water through the resin?
 

anewbie

Well-Known Member
Messages
1,339
So my tap is 130TDS/gh 7/kh 3 - am i better off with DI or RO? Also I need about 100 gallons of ro water a day (when i did a quick search i saw no di unit what that kind of output) ?
 

Frank Hättich

Well-Known Member
5 Year Member
Messages
556
Location
Germany
@Frank Hättich since you don’t have a water outlet, are you using a pump to circulate water through the resin?
I have a faucet in the kitchen from where I pass the water through a hose to my fishroom with the DI-unit and into my 220L water drum. Of course I could also pass the waste water of an RO-unit back into the kitchen. But with my extremely hard tap water and the output of a common RO-unit, it would probably take very long to fill my 220 liter water drum. And my wife would certainly not be amused if two hoses run through our flat and the kitchen faucet can't be used for many hours...
 

Frank Hättich

Well-Known Member
5 Year Member
Messages
556
Location
Germany
So my tap is 130TDS/gh 7/kh 3 - am i better off with DI or RO? Also I need about 100 gallons of ro water a day (when i did a quick search i saw no di unit what that kind of output) ?
100 gallons (450 liter) a day??? How many tanks do you have? With your tap water you should get about 250 liter (66 gallons) of 50uS/cm (TDS 32ppm) water from 1 liter of resin.
 
Last edited:

Members online

No members online now.

Latest posts

Forum statistics

Threads
17,880
Messages
115,916
Members
12,997
Latest member
TheGjboz

Latest profile posts

EDO
Longtime fish enthusiast for over 70years......keen on Apistos now. How do I post videos?
Looking for some help with fighting electric blue rams :(
Partial updated Peruvian list have more than this. Please PM FOR ANY QUESTIONS so hard to post with all the ads poping up every 2 seconds….
我的英语很差,请原谅我!
Top