WATER CHANGE ADVICE

zhonk

zhonk

Crazy Ted
Nov 5, 2006
312
0
0
34
Northwest US
For the first 5 months I had my tank, I used treated tapwater and ocanic salt and a 12% water change every week. While my tanks did have a severe infection of green cyano it was relatively affordable. A few weeks ago the guy who runs my LFS had me start doing monthly 90% water changes with this water he prepares at the LFS with a filter the size of a room that creates pure water and the top brand of salt that apperantly the government uses. This runs for 3$ for 5 gallons. This is 21$ a month and that stretches a little thin on a highschooler budget. Is this necessary or am I just getting ripped off?
 
Thats $0.60 a gallon which isn't bad. Places around here charge $0.75 just for ro/di water. If you want to save in the long run spend $100-200 on an ro/di unit which produces 99% pure water and mix the salt yourself. Heres the breakdown.

Your changing 35gal a month. Thats 420 gal a year.

Cost from fish store $252 per year.

RO/DI $160
membrane lasts 2-3 years ($45 to change)
filters last 6-9 months ($40 to change)

Oceanic Salt (200gal) $39 - $0.195 per gal
Water Cost (1:3 ratio) $0.06 per gal
Thats $0.26 per gal so $109 a year.

So the first year it would cost about $40 more as you would need to replace the filters on top of the inital ro/di unit cost. Although every year after that you would save $60 and not have to lug water around and waste gas doing so.

That being said on my 90 gal (with 10 gal sump) tank I change out 20gal twice a month sometimes only once a month. Thats 20% water change every two weeks.

For your 40gal tank you could change out 8 gals every two weeks or 4 gal every week. I don't see the need to change out any more than that.

So using 8 gal every two weeks thats 192 gal or $115 per year from the fish store. If thats all the water you need than buying your own ro/di you'll break even or just save slightly as its $60 for filters changing every 9 months and $50 for the water and salt. Again from the convenience standpoint its nice.
 
i was mainly talking about the 90% WC. there is no need for that. i would continue with the small WC and buy it
 
Thank you. One detail I forgot to metion is that he sells unsalted water 1$ for 5 gals. I could do this and buy my own salt. What is a good brand of salt and what is the difference between good and bad salt?
 
For fish only and FOWLR, Instant Ocean is very good; if you're going reef, then Reef Crystals would be a slightly better choice.
 
If you have the money go buy your own RO system for less than 150.00 and save more. And why did anyone tell you to do a 90% when all you need to do is 10-15%. Your LFS guy was ripping you off big tie for the amount of water your were changing.
 
lebloom said:
If you have the money go buy your own RO system for less than 150.00 and save more.
Click to expand...

There are big difference between cheap ro systems and good systems. If you are considering buying an ro or ro/di system here are some things to look out for
  • gallons per day -- How much water the membrane will produce in a 24 hour period. Be aware that most 100GPD only have a 90% rejection rate.
  • rejection rate -- Percentage of dissolved solids that are removed from the water 98-99% is what your looking for
  • DI -- Removes the 1-2% dissolved solids not removed by the membrane
  • vertical or horizontal DI -- Vertical is better as it has 3 times the capacity
  • TDS meter -- I like the inline meters that monitor the ro water and the water after the di stage. The meter will get used since its already hooked up and you just press a button. Lets you know when the DI media is exhausted and needs to be replaced
  • flush valve -- When you change out the sediment and carbon filters its a good idea to flush the membrane to remove any solids
  • pressure gauge -- Lets you know your water pressure 60PSI is ideal, too low and you will need a booster pump. My water is 42psi and it works fine still
The combination of the above is what drives the prices and determines if it is a good unit. I highly recommend an RO/DI unit so you have 99.999% pure water.

Personally I started with just an RO unit. I had some ammonia and phosphate left in the clean water. I bought the DI canister for the unit but hated the fact I didn't have a TDS meter, flush valve, pressure gauge, etc. I sold mine for around what I paid as buying all the additional cost more than just buying a new unit.

A TDS meter alone is $35 for the inline one. Without the TDS meter you could be throwing out the DI cartridge before you need to or the opposite and having solids still in the water. Being able to check the output on the RO lets you know your membrane is function properly.

I highly recommend The Filter Guys http://thefilterguys.biz. I went with the old style of the OCEAN REEF + 1. Basically instead of 2 carbon cartridges and the DI on a separate mounting bracket the old style has 1 carbon cartridge and the DI in the main unit. This makes the unit portable as I don't have it permanently installed. It took about $15 off the price, shipped it was around $210.

Yes this is not for everyone, but if you think you'll want the additional add ons get them upfront as its cheaper than adding it later.

Also if your buying water without salt from the fish store you should invest in a TDS meter and check it before you purchase. It should be 0 TDS if your paying an arm and a leg for it.
 
Last edited:
You must log in or register to reply here.
AquariaCentral.com
Top Bottom