Amount of Ca and Mg for my tank

Here's a related question: If my tap water has 20ppm Ca and 1.6ppm Magnesium on average, do I need to dose GH booster?

I've got a 20gallon with fluorite substrate, pressurized CO2 (keeps my drop checker a steady green) and 130 W of light over it. Plants are growing great. So's the algae *sigh*. I'm struggling with green dust algae and the dreaded clado. I'm guessing it's from fluctuating nutrient levels - I haven't been doing proper EI dosing. I've just been throwing the ferts in once per week, after the water change. I'm beyond tired of testing the water, so I'm thinking I'll adopt the EI method, and just dose every other day and do that big water change once per week.

I'm rambling...

Anyhow, is that enough Ca and Mg? If it's not enough of the latter (which I suspect), can the plants pull the Ca from the tap water, and I can top up the Mg with epsom salts?

Other stats on the tank:
pH is around 7.3
using a Magnum HOT filter (love it!) rated 350gph flow. I've slowed it down a bit by putting a sponge over the intake
substrate is fluorite as mentioned, mixed with geosystems gravel (same shape and color, just a sort of inert clay gravel)
hardscape is some natural river wood and river rock (which I boiled the heck out of!) from the Fraser River.
Tank temp is room temperature, about 74F
CO2 is running 24/7 at about 2bps (drop checker is green to yellow-green)
plants are a bit of this and that: ludwiga, rotala, cabomba, some crypts (including parva), some vals, hairgrass, a nice red plant who's name I forget, and some odd and end stems I pulled out of my 90 when I switched it to low light
fauna is a pair of GBR, a bunch of platies, some cherry barbs, panda cories, couple of otos, a bamboo shrimp, a handful of tiger shrimp and 8 amanos.

 

If you cut the light on that 20 gallon tank from 130 watts to 65 watts - remove one bulb - your algae problems will be a lot easier to solve. If you raise the light fixture a few inches above the tank, it gets easier still. You really have far too much light now. Then switching to the EI method will do a lot of good, as would making sure you have good water circulation all over the tank - all of the leaves should be in motion.

 

the lights are mounted about 7" above the water's surface (it's an open top, rimless tank). And the tank is more like 22G (it's a funny size), not that it matters much. 6.5 wpg is high light, I know, but I didn't think it was too high? If I drop it down to 65W, that's just 3wpg, which is only medium light I thought? The tank doesn't look unnaturally bright - it looks quite nice, IMO. Except that I'm having to wipe down the glass every couple of days.

 

IMO, 65 watts over a tank that size should be able to grow about anything quite well. Mind your CO2, ferts and water changes and it'll grow in just as good as it would with twice the lighting.

 

I should've clarified - I've only got the full wattage on for a 3 hour burst. For the remaining 5 hours of my 8 hour photo period, it's only 65W.

 

hello
-I have an 18 liter tank
-How much Ca, Mg must be added when changing water to get 2GH?
-I use CaCl2.2H2O ..... MgSO4.2H20

 

Hello Sir. It is finally my pleasure to introduce myself to a planted tank LEGEND. I HAVE A 40BREEDER. Dutch scape heavily loaded. Im having a hard time growing Pogostemon Stallata. I have saw your post on this specific plant.. i have 122watts of leds hanging 10 to 11 inches above water surface. I have auqa soil and pressurized co2 while dosing Nilocg Diy E.I mix with ex iron. Im having bad stunting and leaf curl.. which leads me to calcium deficiency.
1. 40BREEDER
2. 122watts of led light 11inch over h20 surface
3. Fluval stratum with root tabs
4. Pressurized co2
5. Nilocg D.I.Y E.I MIX +IRON
6. Tank temp 74degrees
7. 8hr photo period
8. Gh5
9. Kh3.5 maybe 4
10. Ph 6.5 6.6
Is there anything you see wrong?? Plz help
I did add seachem equilibrium to my tap. I added 16grams on my last h20 change day and tested gh it was 9gh kh still 3.5 I have seen positive leaf morphology since dosing equilibrium. But is there anything else I can do? Ty for your help Sir.

 

I also have 30 to 40ppm of Co2

 

So if my 40 gallon breeder planted tank dgh is 7 7.5 and has a magnesium deficiency how much should I dose of Magnesium epson salt i do 50% WC WEEKLY 20gal replace of h2o