water changes

[nexusnight]

so I was thinking the otherday  ??? and I was wondering on what is the norm for water changes with evaporation taken into account. I have a 55g and 15g sump that constantly evaporates 5 gallons of water a week. auto top off was a immediate must of course. However at a water change of 20% monthly or even bi weekly, which is where I am at now. is the water change neccesazry this often. over the course of the month im adding more fresh ro water than id be changing anyway. Anythoughts?
thanks

 

[Poseidon]

water changes replenish alot of trace elements that are laced in with the salt mix. so by adding r/o water alone for top off , none of these elements get replenished.

also the waste doesnt evaporate, it will just condense when the water evaporatates, so water changes export the waste.

 

[nexusnight]

makes perfect sense,.... so do you think bi weekly or monthly is better. ive heard you do it to often and it can mess with your params. maybe less changed bi weekly to create the least amount of impact on the system?

 

[Poseidon]

i personally do 30gal water change on my 180gal system, (150g tank and sump) every other week. Which im finding isnt quite enough, ( after about a week and a half i start getting a bit more algae growth)  so im going to switch to 30g every week and a half.

kind of just judge it based on how your tank reacts, im sure others will chime in on this, but i know a good rule of thumb is 10% per week

 

[paoul]

I do 25% weekly

 

[reefin]

I'm changing 20 gallons every two weeks on a 90 gallon tank. Every second Sunday morning. After every water change I start my RODI and replenish the 20 gallons of RODI and 20 gallons of new salt water and circulate and heat the salt water till Monday morning at 7:00 am when we change back to peek hours on the hydro. I then turn the heat and the circ pump back on the Friday night before the water change day at 7:00 pm for the off peek hours and I'm ready to do my water change. So far this schedule works great.   

 

[pulpfiction1]

well lets see,does po4,no3 evaporate along with the water?or are we doing water changes to keep these in check?I've never researched this aspect myself but i don't believe they do,then there is the aspect of lost minerals......I think knowing your tank and doing regular testing will tell you how much and ho often you need to do water changes

JMO

 

[phi delt reefer]

smaller tanks need more water changes from what i find. My "almost" nano setup gets a 5 gallon wc every week or sometimes every two weeks if i get busy. I have a lot of fish so my bioload warrants the extra w/c frequency.  Your other filtration will also determine the need for water changes. A good skimmer/gfo/carbon will help increase the interval at which you need to make the change.

like someone said earlier - its tank dependant, as you get comfortable with your system you will see when you really need to do wc. I like to use my water change to siphon out my bubble algae and other crap that likes to reside in my tank so sometimes the frequency is influenced by my need to siphon crap out vs. water quality.

 

[Jewel]

I change 30 GL bi-weekly on a 150 tank and 30 GL in the Sump. My bio-load is a minumun with 1 fish at the moment. In the future i will increase to 40 bi-weekly

 

[Victoss]

I haven't ever seen a study on it although there may be one out there but from my understanding some things can boil away with water in a gaseous form if they have a similar boiling point but for evaporation I would assume most organics and minerals would be too heavy to evap away. That said who knows there could be a little po4 or no3 evap but I would imagine it would be dismal levels no where close to the levels they are created. Either way you still need to add back the minerals taken away and remove the nasties by doing a water change.

I do 10% on my 55 every other week and 20% on my 29 biocube the skipped weeks (every other week still)

*about 5 gal change each

 

[Duke]

I haven't ever seen a study on it although there may be one out there but from my understanding some things can boil away with water in a gaseous form if they have a similar boiling point but for evaporation I would assume most organics and minerals would be too heavy to evap away. That said who knows there could be a little po4 or no3 evap but I would imagine it would be dismal levels no where close to the levels they are created. Either way you still need to add back the minerals taken away and remove the nasties by doing a water change.

I do 10% on my 55 every other week and 20% on my 29 biocube the skipped weeks (every other week still)

*about 5 gal change each

Agree, these days tho, personally I think to be successful you need to manage nutrient export other ways besides water changes.. U only change water for trace element replenishment, skimmers, bio pellets, and gfo handle nutrient export.

When u think about it.. Water changes do f all to lower nutrient levels when u do the math... 10ppm in 100 gallons with a 10% change would lower you to like 9ppm give or take, if anyone's thinking you can lower your phosphates and nitrates with regular water changes, Imo u can't without massive and frequent ones.