Question about a Constant Water Exchange System

[the buszkock]

How much new water is too much? Is a daily water change of 15% too much? Will the denitrifying bacteria starve to death?

I am putting together a system for a 155 gallon tank + 45 gallon Sump. I have a Zero Waste RO/DI unit that can produce 30 gallons a day. I am planning to plumb the sump to a waste line so that I can continually add water-- constant drip system, you'd call it? I am considering using some sort of irrigation timer if I need to control the amount of water coming in. But if I can simply let it run-- 30/200 = 15% daily change, then I will.

Also, is there a way I can calculate the additional wattage required to keep the water warm enough? Since I keep red belly piranha I try to keep the water around 79-81 degrees. I have two 300W heaters for this system. Will that be enough to keep the temperature stable?

Thanks for any info you can give me.

http://www.monsterfishkeepers.com/forums/showthread.php?p=4891469#post4891469

 

[Blub Blub]

I run a continuous drip with an adjustable regulator. I have changed 30% daily for extended peroids of time when my bio load was large with no problems with my wet dry crashing.

As far as the heaters keeping up I don't think you will have a problem. I can't really say though. As long as the room temp stays above 70f, the lights and heat from my external pump almost keep my heaters from ever cutting on, even with a high drip rate. I guess it would depend on incoming water temp.

 

[the buszkock]

Sounds good then! If I ever find a formula for calculating heating degrees/ watt etc. I'll post it-- but you're right, all depends on how cold the water is and ambient room temp. Once it's all up and running I'll be sure to take some measurements to see how the two heaters are performing.

What kind of regulator are you using? I would love something programmable but I'm not sure what kind of solenoid -- timer to use. I'm definitely looking for ideas anyone.

 

[Dan F]

I am changing about 20% daily right now, but I actually plan on increasing this in the future. I am on a well, so I use straight tap water.

I think you need to rethink using pure R.O. water. From what I've read this can be harmful to fish because of the lack of vital nutrients.

 

[the buszkock]

I am changing about 20% daily right now, but I actually plan on increasing this in the future. I am on a well, so I use straight tap water.

I think you need to rethink using pure R.O. water. From what I've read this can be harmful to fish because of the lack of vital nutrients.

Can you link to your source? I assume that with a well balanced diet, the fish would receive proper nutrients from food sources.

 

[Dan F]

Can you link to your source? I assume that with a well balanced diet, the fish would receive proper nutrients from food sources.

No, I'm sorry. It is mostly here on MFK that I have read this, so maybe somebody can chime in. Most people seem to recommend mixing R.O. and filtered or treated tap water to attain the desired hardness.

It seems to me that it would be fine for species that enjoy a very low hardness. However, many species would probably not do well in water with basically no hardness. What do you keep?

 

[the buszkock]

No, I'm sorry. It is mostly here on MFK that I have read this, so maybe somebody can chime in. Most people seem to recommend mixing R.O. and filtered or treated tap water to attain the desired hardness.

It seems to me that it would be fine for species that enjoy a very low hardness. However, many species would probably not do well in water with basically no hardness. What do you keep?

I keep RBP.

From what I'm reading, Pygocentrus Natterteri require 5-18 dH or 80-320 ppm of calcium carbonate. That's a fairly wide range of water hardness, but you're right, it's not zero.

How might I introduce the proper hardness without using my tap water? The tap here has tons of chlorine and chloramine in it, which is one of the reasons I use the RO/DI system.

http://www.freshwater-tropical-fish-care.com/red-bellied-piranha.html
http://www.fishkeepingforum.co.uk/forum/forum_posts.asp?TID=6526

http://en.wikipedia.org/wiki/Hard_water
http://www.thekrib.com/Plants/CO2/khgh.html

 

[Blub Blub]

What kind of regulator are you using?

Sometimes you can find these a Home Depot in the drip irrigation section. If not they are on Amazon I know. They are made by Raindrip.

 

[Blub Blub]

There are some folks on here that remove chloramines with this filter:

http://www.thefilterguys.biz/chloramine_filters.htm

 

[the buszkock]

After doing more research on this subject I have come up with the following: Pygocentrus Nattereri come from Amazonian rivers that have water parameters along these lines--

Temp. 70-77
higher for spawning
gH 4-14 (8)
pH 6.5-7.5 (7)

When using RO/DI water for freshwater systems, a mineral supplement is required for proper cellular function. The general hardness of the water can be achieve with pure RO.DI water through the use of a supplement. I am going this route because I don't want to use tap to add hardness-- the tap water simply contains too many impurities in my opinion.

Kent makes a product called RO Right that I am going to try. I may even be able to drip the liquid version of the product into a temporary holding tank where the fresh RO water will be housed while it aerates. I am going to bring this plan back to my other thread and continue work on the system there for those who may be interested.

Thanks guy for getting me thinking about gH, kH, pH, alkalinity's effects on cell function, and mineral supplementation. I got quite a schooling this week after being prodded by you guys.

And as always... links to my research.

Water Chemistry in South American Rivers...
http://www.angelfire.com/biz/piranha038/waterchem.html