following on from Candys post in the Takapuna water subject, it would be interesting to see the overall cost of going ASW. Of the two (ASW and NSW) it would be the cleaner - less unknown variables compared to getting NSW from the boat ramp/beach/harbour/side of the boat. But then you would have to look at the cost/benefit of it especially if you live within a minute or two of the sea.

From what I understand there are a number of steps and requirements involved to do it correctly

You need:

Artificial salt mix - Redsea, Instant ocean

Good quality water - RODI unit

Big container - drum for mixing salt/storing salt

Heater - to aid in mixing

How long would the filters on the RODI unit last when using it for both top-up and ASW mixing?

Do people buy the salt in bulk to reduce costs or group buy?

I've gone NSW but I still have some ASW squirrelled away "just in case"

Thoughts? Views?

I did a search of the section and came up with these previous discussions:

Stupid Beginner Questions

Topic tends to drift a little

biggest disadvantage of NSW

Whoops!!!

NSW around NZ

Little bit of info there

No doubt there are other ones too but thats all I could find at the moment

it would cost me 1,780 dollars to do a complete ASW water change on the big tank

that is at wholesale rate too

costs about 40$ and 2 hours to do nsw

It costs me $120 for 700l of asw. I do a 50l change per month. So plz correct me if I am wrong but it costs me $120 for 14 m onths worth of water.

I dont use a heater for the water as I find the pump heats the water enough.

I have an RODI unit already but yes I do use more di resin which probably costs me an extra $80 for those 14 months.

So I am guessing it costs me $200 for 14months of water changes.

Given that I live a 1.5 hour round trip from takapuna and have 2 young children so spare time is limited I just cant see myself ever swithcing to nsw.

Having said that my tank is only 450l total volume, if I had a much larger tank I would probably use nsw

i use asw and use the same 150L plastic drum for mixing my asw as i do for my freshwater topoffs (ie ive worked out a plan so that by the time it comes round to do a water change i should have the required amount of freshwater in the barrel for the water change). I buy the 25Kg Red sea salt mix which costs $127, doing 15% water changes fortnightly on a 400L tank it lasts around 5 months so around $6.30 a week which i don't think is too bad. i was using tap water only for both top ups and salt mixing but now am using straight DI so i haven't worked out how long it will take before the DI runs out (but replacement DI resin was only $11US so its a pretty small amount) i also heat my asw and run a small powerhead

In addition to water changes do you guys do dailyish tank syphoning?

I syphon out around 3L every second day, cleaning out crud and stuff.

for me its:

44L fortnightly (10%) *25=1100

3L every second day *182=546

So 1646L/year of NSW

Plus Top-up water

2L/day =730L

Man the amounts of water I go through starts to add up!

I havent put my hands in my tank for 3 weeks, my sump is different... Only time I am in tank is to vacuum sand and place the odd coral etc