The true cost of a 20g Water Change

[ZoWhat]

I wanted to document what I think are close $$$ numbers on the true cost of a 20g water change.

I chose 20g bc on avg I think most ppl are around a 20g water change when done weekly, bimonthly, or monthly.

TAP WATER TO RODI:

Avg cost of tap water in the U.S. is around $2.50 per 1000 gal (including sewer rates).

If you make 20g of RODI it takes 100g at a 4:1 waste-to-rodi ratio. So 100g of tap costs around 25cents to make 20g rodi

Add the cost of RODI filters. High end 5stage replacement kits cost on the high end $75 to replace filters and resin. Heres where this is an unknown for me. Filter kits I'm guessing need to be replaced at 5,000gal of processing. so cruching the numbers filter kits costs about 2cent per gal... or 40cents for 20g water change

SALT MIX

Most popular brands like Fritz, RS Coral Pro and the like, let's estimate on the high end of $70 per 200g mix. number crunch is 35cents per gal. a 20g WC would then be $7

So some final numbers to complete a 20g WC:

RODI = 25cents water + 40cents filters = 65cents
SALT = $7
TOTAL = roughly around $7.65 per 20g of WC

COST PER GALLON: roughly 39cents per gal to do a WC

WEEKLY 20g WCs = $30.60 per month / $367.20 yearly

BIWEEKLY 20g WCs= $15.30 per month / $187.20 yearly

MONTHLY 20g WCs = $7.65 per month / $91.80 yearly

If I'm missing smthg PLZ ADD to this post



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[SixlineRyan]

I'm in the beginning stages of planning my tank and this is really interesting info. My LFS will sell RODI water for 50 cents a gallon, so thats still going to be cheaper for me, but if I factor in the time and gas getting the water a RODI doesn't look too bad!

 

[PYRU]

Thanks for posting. Its helpful for people like me coming in mindful of maintenance cost. Salt changes are pretty wasteful and bugs me. This gives me peace of mind and hopefully others.

This is around what I had estimated when i asked on my thread the other day.

Salt like IO doesn't make as much as you would think. I think brs had them off 200g by 30g somewhere in there, but you went high with your estimate so it's negligible

 

[Aquavaj]

Cost of water changes aren't really all that much. Depending on how much equipment you have electricity cost might be the higher of the two. I haven't done the math but on my 120 I've been seeing around $30 increase in my bill since starting the tank. And that's with mostly DC pumps, LEDs and a fan for cooling.

 

[jda]

IO can get 44 gallons out of a 50g bag. It is also in the $45 dollar range for the 200g box (4 bags) if you buy smart.

I change water because I am cheap and lazy. $11 to change 44 gallons with a few pennies in RO water and electrical costs... I can change water for 4-5 months for the cost of one ICP test and probably a year if you count the supplements.