seachem makes a magnesium test kit.a reef type test kit may have a magnesium test with the kit,as magnesium works in conjunction with calcium.reef geeks.com is a site to look at for this.or a salt water specialty store can test for it for you.

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i have had the crappiest luck with fresh water fish dying and its NEVER happend to me before!! Can anyone tell me what I need to do to set up a Salt Water Tank??
If you have had problems with fresh water tanks, then salt water tanks will be an utter nightmare.
Before turning to marine tanks, [...]

A few days ago I purchased a 10 gallon aquarium along with other supplies to house two fiddler crabs (from petsmart). One was a female and the other was a male. Both of the them died the other day, and I’m not sure why. I think the mistake I made was that I over salted [...]

Yes I’m cheap, don’t flame me about it. But I am not in the mood to spend about 5 times as much money for something just because it says aquarium salt. So question for those people that use table salt in their tank, what brands do you use? I currently have morton [...]

So I want to get a purple spaghetti eels
but I can’t find anything that tells me what aquarium supplies I need to raise one =(
do I need a heater?
certain sand?
where do I get the salt to make the water "brackish" ?
how much salt do I put in?
what other fish are okay to put in the [...]

Me and my boyfriend currently have a normal tropical tank set up, we put the heater up today. We are planning to buy a pufferfish this friday, we read up that it is essential to keep them in a salt water aquarium? If any of you know if Pufferfish genuinly need to be in salt [...]

I have a fresh water aquarium and I am thinking of setting up a salt water. Is a salt water aquarium hard to maintain?
I’m in the same boat as you. I’ve got 7 very successful and advanced freshwater set ups and I’ve just started with a saltwater nano tank. From what I’ve read [...]

I’d like to set one up after Christmas, but I’ve heard and read some very different and contradicting things about them.
In order to try and get some of the most important things clear, I’m going to try this. Skim through the answers before posting your own; I’ll give a good rating to any answer [...]

In order to have a salt water aquarium with fish only. Leaning more towards predators but not really my point towards question. Can you have a freshwater setup, and change it to saltwater. I ask this because i know live rock is needed when having corals etc. but if it is just fish can you [...]