daily water changes in large tank

[brent waldron]

need some help and recs on best way to set up a system to do daily water changes in a 500 gallon reef tank. do you need to still have a evaporative top off system with DI water in conjunction with your daily changes???? or do you calculate your evaporative losses and take those into consideration with your added amount during your daily water change?????? If you don't continue to add DI for evaporative reasons will your salinity slowly rise over time (as is the case when we do monthly changes) or does the constant daily water change maintain a steady enough salinity without the need for toping off with DI?? also, I was thinking of using a reef doser pump (aqua medic) any feedback/ recs on this pump....... and any recs on how to best set up a daily water change system would really be apprec........ I am currently thinking of a 55 gallon drum for the salt water res and using the reef doser pump to pump out a certain volume of water from the tank and then pumping a certain vol back in. Should I also have a 55 gallon drum with a float valve hooked to a DI unit that is connected to the tank with a top off system for evaporative losses thru out each day????? thanks

 

[seamonkey2]

daily water changes???

why?

I top off my evaporation daily, but tha'ts just RODI water

Jose

 

[Bax]

Yieks! that'll cost a few buck$ to operate.

I like weekly changes myself. 10 - 20 % depending upon what happening in the system.

 

[Ixthys]

Daily or even continuous water changes are somewhat easily done. Randy Holmes-Farley did an article a while back on the subject and showed it was nearly as effective as weekly or monthly changes.

Water changes are done with saltwater. Top-off is done with RO/DI water. I think it would be too confusing to combine the two.

 

[dgasmd]

Can be done, however, overly complicated and costly to say the least. You would need to add enough new water daily to replace all the used Ca and Carbonate extracted from the water. My best guess is that depending on where your bioload is, that percentage of new water has to be close to 3-5% of your total volume. That means that for a 500g tank, you you would be adding 25 gpd on a continious basis and letting the same volume overflow out to a drain. Top off would be a nightmare to try to adjust, but my best guess is that you wouldn't really need it. It would be nearly impossible to dial in a Ca reactor as you are adding in Ca and Alk daily and varying the levels with the new water.

Just so you know, ORA uses this method in their aquafarm. They add about 5% of their total volume daily and use heavy skimming, chillers, and UV on top of that. That can get very very expensive quickly. I entertained the idea briefly until I saw the numbers.

 

[Ixthys]

The chemistry industry has plenty of dual-pumps that remove the same amount from one of the pumps as it adds with the second pump. Again, though, I would NOT combine your "water top-off" with your "water exchange". Otherwise, things will get very complicated.

I do it with a reef-filler pump. Check out

http://www.championlighting.com/home.php?cat=386

Basically, one of the pumps pulls from a saltwater holding tank and pushes the new saltwater into the refugium, while the other pump pulls from the sump tank and dumps the waste into the sink.

I have a 100gallon tank I store the new saltwater in. I think I have the pump set for 6 gpd = 180gallons/month. On my system this is equal to a 50% monthly water change.

 

[Chaotic Reefer4u]

wow some very informative stuff here guy's...

 

[brent waldron]

ixthys,

thanks for your feed back.....so you are basically pumping out 6 gpd from your tank and then pumping 6 gpd from your salt water vat back into the tank with this pump... what about the evaporative losses thru out the day??? is this accounted for? (lets just say mine evaps a gallon a day) should I then only pump out 5 gallons but return 6 gallons from my saltwater vat??? will my salinity remain constant since I'm not using any DI water to off set the evaporative losses (hence inc salinity) ???

 

[clekchau]

<a href=showthread.php?s=&postid=8623060#post8623060 target=_blank>Originally posted</a> by Ixthys
The chemistry industry has plenty of dual-pumps that remove the same amount from one of the pumps as it adds with the second pump. Again, though, I would NOT combine your "water top-off" with your "water exchange". Otherwise, things will get very complicated.

I do it with a reef-filler pump. Check out

http://www.championlighting.com/home.php?cat=386

Basically, one of the pumps pulls from a saltwater holding tank and pushes the new saltwater into the refugium, while the other pump pulls from the sump tank and dumps the waste into the sink.

I have a 100gallon tank I store the new saltwater in. I think I have the pump set for 6 gpd = 180gallons/month. On my system this is equal to a 50% monthly water change.

very interesting, can you provide more details on how your daily water change system works and how the reef filler accounts for evaporation?

 

[bradleyj]

Salt does not evaporate. Your top off water needs to be just that..water. If you replace your evaporated water with salt water, your salinity will climb.

 

[brent waldron]

bradleyj, that is correct so are you suggesting that I have two seperate systems one for evaporative losses and one for daily changes..... this is what I was originally thinking of doing... having a three stage reef doser pump. one stage will pump out the designated amount of salt water , then another stage will pump in that amount from my salt water vat. The third stage then could be attached to my DI resevoir and each day pump in DI water to cover my evaporative losses. Will this work??????? I understand about salinity and salt water evaporation, but I wasn't sure if doing daily changes would be enough to maintain a steady salinity in and of itself.... apprec all of the feed back!!!!!!!

 

[seamonkey2]

Let me say first that, I do a water change every 6 months or so, in a well populated 240ga display(90ga sump and 40ga refugium),
I add about 2ga a day as top off RODI water

I run a ozone machine 24hrs and my fish are fat and happy

remember every tank is unique to itself and how you run your tank is up to you, what works for me, may NOT work for you

but here is what its suggested:

one peristatic pump removes water from the tank at a set amount, lets just say, 5ga a day

another pump puts fresh SALTWATER from a reservoir back in the tank at the same rate 5ga a day

at this point the water taken out is replaced evenly

a third pump is use for top off ONLY and it pumps fresh RODI water at the evaporation rate for this particular tank, lets say 2ga a day

this way there is not over salinity nor confusion of what is what.

the most important thing is to get the correct amount of fluids going out or coming in, once you figure that out is easy money from there

Good luck

Jose

 

[seamonkey2]

and I was typing at the same time as Brent was

you got it Brent, just remember to double check your eveporation rate first for the top off

Jose

 

[Ixthys]

bradleyj is correct.

I can't say this strong enough, but DO NOT TRY TO COMBINE WATER EXCHANGE AND WATER TOP-OFF!!!

Water that evaporates daily should be replaced with the same amount using RO/DI water.

Water that is Exchanged with a pump should be 1:1 saltwater. The reeffiller does not account for evaporation. I use a Tunze topoff unit for that.

EDIT: looks like I was typing along with everyone else!

 

[Ixthys]

By the way, I am not pumping out 6 gallons, and THEN adding back in 6 gallons. The pump runs continuously 24/7 constantly adding and removing saltwater.

I know this may be counterintuitive to some, and yes I am taking out some of the "new saltwater" that I am adding, but it is only on the order of a couple of %.

 

[clekchau]

i understand that salt does not evaporate....

my question is, how do you control evaporation in your resovior for water changes, not top off. let's say you change 10 gallons a day, in your resovior some of that 10 gallons will evaporate, how do you consistently maintain a stable salinity thru your daily top off system.

hey jose, how's it going?

 

[seamonkey2]

whats up buddy
got the 600g up un runnig yet?
BTW if you want the pair of bird wrasess(female and male) we can talk

to control the evaporation in the reservoir, you will have to know the exact amount of evaporation in that container and mantain a fresh water supply to it to maintain the exact salinity, with the use of a float valve or top off system, so basically another pump from the RODI to the reservoir

Ixthys, you macht the exact amount of saltwater out with saltwater in, using the pumps, the amount of water exchanged does not matter

Jose

 

[clekchau]

hi jose, are they your fish or someone else's? i trust you, i don't know if i trust a random person selling fish =D. tank is being delivered this friday, i can't wait!

so basically you would have 2 top offs, one for your evaporation on the main tank and one for your resovior , and in the resovior it's constantly emptying 24/7....argh sounds like a pita i think i'll stick with my bi weekly water changes.

 

[seamonkey2]

nope they are mine, I would not sell some one else's fish, I had them for close to a year, I am getting rid of them because they like to eat the clowns eggs, and the clowns are not happy
so bye bye they go


yes, is a pita, also you wouldn't be able to control the reservoir tank salinity unless you also constantly add salt to be mixed with water for mixing and top off, since it would constantly be added to the tank

Jose

 

[Ixthys]

Hmmm, I must not be doing a good job of explaining b/c it is not a pita. Maybe if I give a little more detail about my system..

I have two 100gallon tanks in my fish room. The top one holds RO/DI water and has a drain w/ valve running to the tank below. The tank below is for making new saltwater. I fill the top tank up with ro/di water, open the valve to the tank below, and add 2 bags of 50g salt to the lower tank. I close the valve and refill the ro/di tank.

For saltwater exchange: a tube runs from the lower tank (new saltwater) to the dual pump and into the refugium. a second tube runs from the sump to the dual pump and into the sink. Over the course of the day 6 gallons of saltwater are exchanged without me ever touching anything. The onlything I ever do is make sure that there is new saltwater in the lower tank.

For evaporation: I have a tunze topoff system in the top tank with ro/di water and a sensor in the sump. As freshwater evaporates over the course of the day and the water in the sump drops, the tunze pump kicks on and sends ro/di water into the sump.

The two systems work independently of one-another. Since the Saltwater exchange is continuous, there is no water level fluxuation and therefore it doesn't effect the tunze makeup water for evaporation.

Hope I did a better job this time explaining things.