soulsigma
Member
So what about Reverse Osmosis (RO)?
Reverse osmosis is basically when water is passed under pressure through a series of prefilters, to remove particles and chlorine, and finally a membrane designed to allow water molecules through but trap everything else present. An RO unit on average, will remove 92 - 97% of the dissolved solids that your water contains. To remove the remaining dissolved solids, most quality RO units will have a DI (De-Ionization) pod at the end. This will then, as previously mentioned, give you pure water for mixing your chosen salt with. The DI filter is capable of polishing 100% of the dissolved solids out of your water on its own, but it's costly, hence the reason a mixture of filters are used.
How do we measure the quality of our water?
To monitor the quality of our water we use a TDS (total dissolved solids) meter. TDS meters measure the amount of organic or in-organic substances that are present in water. The higher the TDS reading you get, the more unwanted properties your water contains.
There are 2 main types of TDS meters that are used by marine keepers, 'hand held' and 'in-line', both are very affordable costing about $15 - $25. The in-line meters are preferable if you have your own RO unit. These meters normally have a before and after reading, meaning you can see what the TDS is of your water before the filtration process and the end result allowing you to replenish your DI resin in plenty of time, and check your membrane is working ok.
Hand held meters can be used when you're buying your RO water from your local fish shop, or producing your own.
How much will it cost me to produce my own RO water?
The most cost effective way to use RO water is to buy your own unit. For example a 50gpd (gallon per day) four stage RO unit with the added DI resin pod should cost under $100.00
Most LFS will sell RO water as well, but the quality of the water will vary from shop to shop, most LFS wont filter the water through a DI unit meaning the water will more than likely be of a lesser quality than if you owned your own unit. Buying RO water from your LFS, is not really cost effective either, costs average between $2 - $4 for 10 gallons. So you can see after a year of buying water from your LFS, you will have probably spent more money than if you were to buy your own RO unit, for water that's of a poorer quality.
There are running costs to a RO unit, the prefilters which protect the membrane have to be changed at regular intervals, recommended every 6 months dependant on use. But these very occasional costs still add up to being much cheaper than buying your water. It isn't easy to work out exactly how much say 10 gallons would cost, there is just so many factors involved, but one major manufacturer (RO-MAN) says that working off some standards that have had to be set, it works out about .39 per 1 lgallon of RO.
Would it not be cheaper to just use tap water???
At this stage is may appear that tap water is the cheaper option over buying or producing your own RO water, but in the long run this will not be the case. To counter-act the poor quality water being used, more equipment will likely be needed to reverse the effects of your tap water, such as a phosphate reactor. Add to that the monthly if not fortnightly renewal costs of the phosphate removal media, and the fact you will need certain additives to balance your water parameters it is not a cheap option. In the long run, RO water is cheaper, and the better option for your tanks inhabitants.
A picture of the same sand bed after switching to RO water for 7 months and adding some phosphate remover
Reverse osmosis is basically when water is passed under pressure through a series of prefilters, to remove particles and chlorine, and finally a membrane designed to allow water molecules through but trap everything else present. An RO unit on average, will remove 92 - 97% of the dissolved solids that your water contains. To remove the remaining dissolved solids, most quality RO units will have a DI (De-Ionization) pod at the end. This will then, as previously mentioned, give you pure water for mixing your chosen salt with. The DI filter is capable of polishing 100% of the dissolved solids out of your water on its own, but it's costly, hence the reason a mixture of filters are used.
How do we measure the quality of our water?
To monitor the quality of our water we use a TDS (total dissolved solids) meter. TDS meters measure the amount of organic or in-organic substances that are present in water. The higher the TDS reading you get, the more unwanted properties your water contains.
There are 2 main types of TDS meters that are used by marine keepers, 'hand held' and 'in-line', both are very affordable costing about $15 - $25. The in-line meters are preferable if you have your own RO unit. These meters normally have a before and after reading, meaning you can see what the TDS is of your water before the filtration process and the end result allowing you to replenish your DI resin in plenty of time, and check your membrane is working ok.
Hand held meters can be used when you're buying your RO water from your local fish shop, or producing your own.
How much will it cost me to produce my own RO water?
The most cost effective way to use RO water is to buy your own unit. For example a 50gpd (gallon per day) four stage RO unit with the added DI resin pod should cost under $100.00
Most LFS will sell RO water as well, but the quality of the water will vary from shop to shop, most LFS wont filter the water through a DI unit meaning the water will more than likely be of a lesser quality than if you owned your own unit. Buying RO water from your LFS, is not really cost effective either, costs average between $2 - $4 for 10 gallons. So you can see after a year of buying water from your LFS, you will have probably spent more money than if you were to buy your own RO unit, for water that's of a poorer quality.
There are running costs to a RO unit, the prefilters which protect the membrane have to be changed at regular intervals, recommended every 6 months dependant on use. But these very occasional costs still add up to being much cheaper than buying your water. It isn't easy to work out exactly how much say 10 gallons would cost, there is just so many factors involved, but one major manufacturer (RO-MAN) says that working off some standards that have had to be set, it works out about .39 per 1 lgallon of RO.
Would it not be cheaper to just use tap water???
At this stage is may appear that tap water is the cheaper option over buying or producing your own RO water, but in the long run this will not be the case. To counter-act the poor quality water being used, more equipment will likely be needed to reverse the effects of your tap water, such as a phosphate reactor. Add to that the monthly if not fortnightly renewal costs of the phosphate removal media, and the fact you will need certain additives to balance your water parameters it is not a cheap option. In the long run, RO water is cheaper, and the better option for your tanks inhabitants.
A picture of the same sand bed after switching to RO water for 7 months and adding some phosphate remover
