Ok, I think I am going to get my 240g running this coming week. I didnt get any responses about my dosing really in a previous thread so thought I'd start a more specific thread. BTW my tank build thread on TPT is here: My 240g build journal, latest pics: filtration - The Planted Tank Forum

Ferts: Will be using KNO3, KH2PO4, and Flourish. I also have some MgSO4 but not sure if that will be useful or not. I was hoping to use TPN but can't seem to find it in the big bottles anywhere in stock so I am trying flourish for the first time. Also trying to locate a supplier I can get some bulk bags of KNO3 and KH2PO4 but no luck yet.

Dosing: I've not seen any dosing for ~300g so what I did was multiply the 90-125g dosing from the EI light thread by 3 for roughly 300g (240G tank, 66g sump, of course actual water volume is slightly less) so thats 4 1/2 tsp KNO3 x3 per week, 1 1/2 tsp KH2PO4 x3 per week, 90ml trace x 3 per week. Man thats a big jump from my 75g.

But here is the twist. I am going to try my hand at automation with some DIY liquid dosers. Only thing is as far as I can tell I cant set my timers to different days, meaning each is to dose each day. And for the sake of freeing up a timer I'd like to just dose em at the same time. Though they will be dosed into opposite sump tanks (I'll have two sumps) and the concentrate tanks will be separate.

So the weekly amount from above:
4.5tsp KNO3 X 3 = 13.5 tsp (rnd to 14) / 7 = 2 tsp daily KNO3
1.5tsp KH2PO4 x 3 = 4.5 tsp / 7 = 2/3 tsp daily KH2PO4
and 90ml x 3 = 270ml / 7 = 38.6ml rnd to 40 ml daily Flourish

Do these numbers look good? Did I miss anything in the math? Would additional Mg be any good (or anything else for that matter)?

I will also be doing daily water changes with tap water run through micron and chlorine guzzler filters. I figure 10% daily will yield roughly 50% effective weekly change (but havent done the exact math).

And since my plant load will start out much less than 'heavy' I figure starting off at 50% dosing levels. Any suggestion appreciated, as I'd like to avoid algae at all costs. I also will most likely not through any fish in there right off the bat either. If there is no fish would it be any good to increase co2 over 30ppm starting out? The first batch of fish will probably be the algae crew whenever it is, SAE's, flag fish, ottos, and BN plecs.

It looks to me like you are 50% too much KNO3, but ok on the others. I would ignore the sump volume and dose accordiing to the volume containing plants. So, 125 gallon tank gets 1.5 tsp, 3X per week. You have about double that amount of planted volume, so that would be 3 tsp, 3X per week. Then X 3 to get weekly total, and divided by 7 to get daily dose, or about 1 1/4 tsp per day.

I would also start dosing the full amounts from the beginning, and rely on the 50% weekly water change to take care of the excess.

Hey,

I used the 100-125 gal EI dosing as a base for my 180 and I ended up with the following:

+/- 3.0 tsp KN03 3x a week (N)
+/- 1.0 tsp KH2P04 3x a week (P)
+/- 45-50 ml Trace 3x a week
50% weekly water change with Prime

So for a 240 which is 1/3 again as large as mine, I would add about 35-40% and end up with:

+/- 4-4 1/4 tsp KN03 3x a week (N)
+/- 1.5 - 2.0 tsp KH2P04 3x a week (P)
+/- 65-70 ml Trace 3x a week

However, Vaughnh has more experience than I.

I agree with Vaughnh and think you should dose 100% from the start.......

Your water change schedule should handle any overages....

I would also plant heavily with stem plants or vals at the start as you get things going. You can always replace with something else later......If these plants don't grow well, you know something is not right.

Good luck. Please post some pics!

VaughnH - you might be right about the OD on KNO3... after re reading the numbers , I rounded up twice too so your figures might be more appropriate. You bring to light one question I had, is the nutrient dose based on plant mass or attaining a certain concentration in the water. If for plant mass, you could take all the plants out of a 55 and put them in a 240 and dose the same amount because the plants are the same. But if you tested the nitrate and phosphate like so many do you'd get really weak concentrations, which is why it seems we are dosing for a certain concentration (that would include all gallonage in the system like sump tanks, etc). Not that it really matters, just something I've often wondered about.

Thanks also Gerryd, I'll make some adjustments and use that for my base dosing. I figure of course I might have to make adjustments later as well. On my 75G I am higher than IE dosage and still struggling with maintaining nitrates at 10 or more... but on the 240g it wont be that dense even when its full I dont think.

I'll reduce the KNO3 some but it should be dosed at 3X the K2PO4 correct? That would mean I need to also reduce K2PO4 since my figures maintained that 3:1 ratio.

Ok it would be a lot easier dosing the full amount from day one if you guys really suggest that. I will try some fast growers to start out with also, I am just not sure if I am going to really be able to fill the volume, I am going to have to add a lot extra. My long term goal is to not have any fast growing stems - at least ones that need trimmed, I'm hoping this will be a low maintanence type setup once it gets going. I dont want to have to actually get in the tank any more often than every month or two. And I might have to empty out all the local stores for stems But I guess I can always sell off the stems on the forums when my main plants fill in,maybe re coupe that cost. I do have a little rotalla in my tank right now that I havent been able to completely remove, that stuff grew like it was going out of style.

Hey CL,

I just went to your linked site and saw your web site........How did you unload that tank by yourself??????????? Are u Hercules lol......

You state that you have will have 432 wpg (8x54). Plus you will dose full EI, this does not square with your last statement of a monthly pruning, low maint type tank.

If you are also planning on using c02 (??), then you are a high tech tank my friend....

You don't have to buy as many plants as you think.

If conditions are correct, the stem plants will grow quickly and you can use top trimmings to fill out the rest.

E.g, I planted about 6-8 stalks of Hygrophila difformis about 4-5 weeks ago and they have multiplied hundredfold and are all over................I have already had to remove large bunches of it.

Stem plants like Bocapa, Rotala, Hygro, etc will grow as much as 1/2-1" daily under good conditions and will sprout many side shoots as well.

1. What size pump will you use for this tank? just curious.

Good luck.

P.S. I used flourish at first but switched to TMG for trace. I like it a little better, and Tom and a lot of folks recommended it

I admit that I am not sure if you should count the volume of water in a sump when you figure out your EI dosage. I can think of reasons to count it and to not count it. When Tom returns home he can explain this.

I have a 20-30 gallon sump.

I also have a 3" layer of substrate.

I figured that the sump volume replaces the water volume displaced by the substrate, rocks, wood, etc.

So, I figured 180 gal volume for dosing..........

Maybe your setup would work out the same, 66gal sump vs displacement of subs/decorations so maybe it is moot point?

I am also interested in Tom's opinion on this........

What type of substrate ARE you using? If nutrient rich, perhaps your EI or trace dosing can be slightly less?

I agree that you should adjust as you go along until you find your optimal strategy........

Vaughnh, your opinion on this?

EI is an estimative way of dosing, not a precision way. So, unless the sump is comparable in size to the tank it probably makes no real difference whether you add its volume in or not. And, It is certainly true that the thick substrates we use displace a lot of water, further reducing the process to an estimate. If I had that big tank and sump I would ignore the sump volume for two reasons, first that the actual quantity of water in the tank is considerably less than its internal volume, and second, the plant mass is at a minimum when you first set up the tank. After a few weeks I might decide that my plants were growing slower than I expected, and then I would increase the dosing. But, it isn't an important thing to calculate.

Thanks guys for all the feedback, sorry its been a few days since I signed in.

Hi tech doesnt have to be high maintanence. I already have a high tech 75G with right about 3wpg and pressurixed co2. I dont trim plants. But then again the tank never had a theme or a real scape just a wild jungle

I just tend to avoid stems as all - thats the mainstay of the 'trimming'. The only stem I actually want to try for the actual scape is blyxa japonica (never had it before though). But I will also add some more stems for starters at least.

Its actually going to be 8 x 80W since the ballast I'm using overdrives the 54W bulbs to ~80W. But thats in two banks so its actually only going to be like 1.3WPG for the day except for the 'noon burst' which I'll have to play with the duration. I get a wide range of opinions here. Some even say the full 8x80 wont even be sufficient and them some say its plenty. Due to the tank size I am hoping the 'larger tank dont need as high wpg' pans out.

Yes co2. No for nutrient rich substrate, its just PFS. But will use root tabs. I have a bunch of Tropica tabs as well as I am in on the order of 'medecinemans' tabs on the group by on TPT.

Yeah I know EI is just an estimate... hence the name. I assume I will be adjusting along the way, just trying to figure out a starting point and maybe an idea which way I may have to head after that. Which reminds me of another question... should a do a really big dose at first just to get the levels to normal? I havent done the math but I suspect the normal EI dose on a tank with plain water wont actually raise the levels that much? Or maybe since the plant load will start so light it will balance out. Hmmm

Hercules? I wish, but it was actually easy. I made rails of like 2x8's or 10's leading onto sawhorses about the same hieght as my truck so there was no lifting involved, just sliding. And its easy to slide with rollers (like wooden dowels or segments of PVC pipe).

The sump is two totes equalling 66g. I estimate that just about 10g would reverse siphon through my spraybar if the power failed and my check valves failed. So the highest I'd fill the sump would be about 50g for a good margin of safety (still have to do some more testing though). My average depth of substrate is 3" so thats 30g right there. But I forget how much of that is still water, I'll assume 10g. Plus the extra inch on top is 10g, so I am at 210 gallons not counting driftwood, fish, overflow chanber, glass thickness etc. I'd guess 200 is a good estimate, plus 50 in the sump. So even with the big sump I am barely at the 'nameplate' rating of the tank as far as how much water is in the system.

Dang... I just did some more math, at double the 90-125 EI dosing for trace, I would be at about 1L per month of trace (I calculate out 1.157L for 30 days). Yikes! Is Tom's cheaper micro mix ever going to come out I wonder....

Big Tank$ mean big buck$!! Blyxa japonica is a great plant, but if it grows at all well you won't be able to get by with pruning it once every two months. When it grew for me I had to be involved with it about once a week. Unlike typical stem plants it generates new plants alongside the original one, and as they start getting crowded, the new ones just grow suspended in the water. When I would thin it out I usually reused only about 20%, if that much, of what I removed. But, it is such a beautiful plant!