How many of you actually dose Mg(Epsom salt)?
What are the signs of deficiency or dosing too much?

i sprinkle a bit at water changes, more for helping my livebearers remain proper electrolyte balance in my soft tap water... also add baking soda for KH and dose K+. so Ca is the only major electrolyte that I don't add in some form, and I'm thinking of starting, as my plants are showing Ca deficiency or K+ overdose, can't tell which (if there's really a difference). So short answer, yes. just a pinch or two per 30 gallons. is it necessary? probably not if you have a decent GH or fish and plants that do ok in soft water. I'm about 50/50 on both counts... fish are mix of fish that like moderately hard water (livebearers, american flagfish..) and fish that like soft water (gouramis, soft water dwarf cichlids, cory cats, dwarf plecos (clowns and bristlenoses). I really just tried it as an experiment because I was losing lots of livebearers, and lost all my celebes rainbowfish.. thought the low GH might have had something to do with it. As far as your plants are concerned... it's doubtful you'll run into any real trouble without dosing it, but it's definitely *possible* to burn through it in a high light, high CO2, EI-style setup. signs of deficiencies can be found here:

http://www.csd.net/~cgadd/aqua/art_plant_nutrient.htm

Mg deficiency from that site:

Yellow spots
Often appears similar to iron deficiency since mg deficiency prevents a plant from properly using iron.
Yellowing of old leaves starting from edges while major veins remain green

I should also note that I dose iron pretty heavily to try to color up my crypts, ludwigias, and ceylon hygro, if i'm adding excess Mg, it's likely being assimlated during iron uptake, which I'm trying push for redder reds. I really rambled WAY more than I meant to in that post. Hope it helps somewhat.

Oqsy

I sometime mix it in, but usually when I do, its mixed in with my Plantex CSM+B solution (1 TB + 250 mL H2o, and roughly 1 tsp epsom salt). I add this every other day (5-6 mL).

I just dose Magnesium when I do watter changes to get my gh back up to 80 ppm. To raise my watter's gh, I add 50% calcium amd 50% magnesium untill my watter's gh is back to where I want it. Since magnesium and calcium are trace nutreince, they dont really need to be dosed regulary. Just dose these things after water changes to bring your watter hardness back to the level where you want. If you dose 100% magnesium or 100% calcium to raise your water gh, you will probably run into deffeciences in one of the two nutreince. Thats why I believe magnesium is best dosed 50/50 with calcium.

I use RO/DI water for my water changes, so I add it.

I raise the GH of the water by 6 degrees. To do this I add calcium and magnesium in a 4:1 calcium:magnesium ratio based on molecular weight.

I mix mine in with my Plantex CSM+B solution

I have read a lot about mg recently. I have just recently aquired some mg and I am going to start including it in my WC.

jB

My GH is >10 and I recently discovered that I had an Mg deficiency. Check out this recent thread (https://www.plantedtank.net/forums/sh...ad.php?t=20821). It seems that Mg deficiency is actually somewhat common.

For me, the primary symptom was stunted, twisted leaves on my Alternanthera reineckii. I think it is also the reason that my stellatus has struggled. If you look at the last couple shots in my photo album (https://www.plantedtank.net/forums/sh...9&page=4&pp=15) you should be able to see the differences in the reineckii (back left corner) and stellatus (to the right of the reineckii).

My symptoms didn't match what Chuck Gadd has posted. My symptom actually match the Ca deficiency more closely.