NSW Replacement

[kiwis]

So I'm finally looking to set up my Marine Aquarium and plan to use NSW.

My question is. Over the course of a week water will evaporate from my tank leaving a more salty water base. When I do a 20% water change using NSW it'll just replace some of the fresher water with normal balanced NSW making it slightly less salty again - but overtime I will get away from the perfect balance (rather quickly I would think).

How do I bring this back to a normal balance?

I assume using marine salt?

Is that correct?

How does one calculate how much new salt is required to a a tank to balance it correctly?

[#!CrunchBang]

You replace evaporated water with fresh/pure water. because when the water evaporates, it leaves everything else behind.

You will have to add top up water often, as the amount that evaporates is quite a lot more than a fresh water tank. calculating how much water to replace is probably bloody difficult, it's better to add a mark on the outside of the tank to let you know where the water height should be for when you replace the evaporated water.

Also, NSW is higher in salinity ~40ppt, so you will have to dilute it with RO/DI water to get to ~35ppt. Used a refractometer to measure this.

[Adrienne]

You replace evaporated water with fresh/pure water. because when the water evaporates, it leaves everything else behind.

You will have to add top up water often, as the amount that evaporates is quite a lot more than a fresh water tank. calculating how much water to replace is probably bloody difficult, it's better to add a mark on the outside of the tank to let you know where the water height should be for when you replace the evaporated water.

Also, NSW is higher in salinity ~40ppt, so you will have to dilute it with RO/DI water to get to ~35ppt. Used a refractometer to measure this.

Good advice - Until I set up ATO on my tank I was putting in around 3 litres of RO water per day to handle evaporation. It needs to be topped up frequently as besides the salinity increasing during evaporation, the skimmer won't cope as well with changing water levels.

[Ira]

So I'm finally looking to set up my Marine Aquarium and plan to use NSW.

My question is. Over the course of a week water will evaporate from my tank leaving a more salty water base. When I do a 20% water change using NSW it'll just replace some of the fresher water with normal balanced NSW making it slightly less salty again - but overtime I will get away from the perfect balance (rather quickly I would think).

How do I bring this back to a normal balance?

I assume using marine salt?

Is that correct?

How does one calculate how much new salt is required to a a tank to balance it correctly?

Yup, pure RO water, it's literally one of the first few things mentioned in any marine tank care guide.

[kiwis]

a drip system would partly solve this? obviously the drip supply needs topping up as i wouldnt use tap water.

how do you guys get your RO water?

[livingart]

ATO = automatic top up

Either pure dew purchased from super market or a reverse osmosis de-ionizing system

[Adrienne]

What sized tank are you planning? The size will most likely make a difference to whether you need put an ATO on it and also whether you use the likes of Pure Dew or an EO/DI unit.

[kiwis]

whats a EO/DI unit?

[Adrienne]

oops RO/DI unit

reverse osmosis or reverse osmosis deionizer unit

[91 ZERO]

Yup RO water to top up if some has evaporated. You may find you don't have to top up the tank at all, time will tell.

1. Select the salinity constant you want to keep your tank at and try and keep it at that. I aim to keep ours at 1.025. Try not to keep a "range" as your constant, as it can make it more difficult to gauge what your tank is doing in terms of salinity changes and the constant varying salinity could stress livestock.

2. Once your tank is at your desired salinity level (and you have your right amount of water in the sump with tank operating normally), make a little mark on the sump at the water level. If it drops below this level, top up only with RO water. Don't use tap water, unless you are really stuck. However don't stress if you have to use tap water, just definately do not make a habit of it.

3. Prior to doing a water change, check both your tank salinity and also the salinity of the replacement water. If your salinity has gone above your desired level you can either top up to your mark with RO water and then do your water change (this can be wasteful as you will then be draining water), or you can adjust the salinity of the replacement water prior to doing the water change.

For example, my very un-scientific method (based on my 1.025 constant)

Tank salinity 1.025. Replacement water salinity 1.025 = no adjustments, just do water change.

Tank salinity 1.027. Replacement water salinity around 1.022 = this should help drag tank salinity down.

Tank salinity 1.023. Replacement water salinity around 1.027 = This should help pull tank salinity back up.

This takes practice but you get the idea.

[kiwis]

thanks- great response. and you use marine salt from the local fish supply shop to increase the NSW salinity?

[Ira]

thanks- great response. and you use marine salt from the local fish supply shop to increase the NSW salinity?

No, most local NSW if anything you need to decrease it by adding RO water. I recall it generally being around .028, at the very top of the suggested range. Though, you're probably better off using it straight unless you have something really touchy. Save you some work.