dosing brightwell but no po4

[becon776]

my tank has been set up (rsr450) for about 1.5 yrs. I've had some struggles but those are mostly irrelevant (except 2x dinosaurs outbreak).

I have never registered PO4. ALK and Ca usage was virtually nil. so I decided to take the two part offline and start dosing brightwell. no3 and PO4. Initially to bring down NO3 (new autofeeder) which it did. now NO3 sits at 5-12 (was 30).

ran calculations and started off with 14 ml po4 per day and 20ML NO3 (Since it is already present). this was a month ago. about two weeks ago upped to 17ml PO4 and 30 NO3. as of a min ago I upped PO4 again to 24ml/day. since beginning my alk and Ca are dropping. about .1 -.2 per day. I only have one DOS right now. I am going to have to shotgun dose either the two part or the nutrients. which one should I be "shotgunning"????????

 

[chromis]

You do not need to dose nitrate if your nitrate is already 15ppm. If nitrate is high and phosphate is zero, you want to only dose phosphate so that your tank can utilize the nitrate that is already present (sounds like your system is phosphate limited).

Make sure you have a good phosphate test kit like Red Sea which can measure phosphate in the low range - if you consistently measure 0ppm phosphate, even after dosing phosphate, it’s likely your kit doesn’t have enough resolution.
Also dosing 24ml of Brightwell phosphate to a RSR450 (~100g) should raise phosphate by about 0.08pm which is a lot, and if that is not measuring any phosphate on your test kit, you should check your kit.

My advice is to continue auto-dosing Alk and Ca and only dose phosphate by hand once you figure out what is going on with your test kit.

 

[becon776]

it hanna lowrange. I tested a standard that I got from fauna Marin on b.r.s. it was within .01.
up until recently I had been trying to get Triton method with a custom Triton sump. never was able to register po4... ever. BUT I had a HUGE fuge with h380 cranking a full reverse photo period over it. was pulling a bathroom garbage can out every week. nixed that bc couldn't live with no mech filter. so now switched to trigger platinum 34 and I cut chaeto to 10% of what i had and reduce light to 3hrs / nt.

tell me about the PO4 addition, I couldn't believe that i still had zero. I think my PO4 has been limited for so long it's just soaking it up like a sponge. my thoughts are to keep with the dosing until I start registering a po4 level then taper. I think since my daily bionic addition is just 6.5 ml to take care of the .10 drop in dog I will hand dose. and look into a second DOS.
if I test zero PO4 I'm raising it to 30 ml/ night. I will back off NO3 but if at any time I feel I'm running to rich I can easy trim dosing the fire the afterburner with h380 and will soak up NO3 like a sponge (and po4)


I gotta think that the tank will saturate at some point. to think I avoided buying pukani rock bc I was scared it would leach phosphate lol

 

[becon776]

ok tonight's measurements (always after lights out) are:
PO4- .025ppm average of two tests
NO3- 5ppm via Nyos unchanged despite adding 30ml of neo nitro

holding for now. if tomorrow tests show a marked increase then shows tank is become saturated will back down to 17ml/day

just for extra credit attaching basic parameter screenshot

 

[becon776]

tonight measurements were
PO4- .06 ppm
NO3- 25 ppm

adjusted PO4 from 25 ml/day to 14ml/day
adjust NO3 from 30 ml/day to 0
I did adjust my auto feeder bc I discovered it wasn't releasing anything due to pellet size. now it is feeding 4x's/ day spectrum. I am thinking of cutting to 3 since I am home now.

 

[becon776]

I'm just gonna keep updating
Po4- .05ppm
dosed 14ml

NO3- 12ppm
dosed 0

Now last night it was late. Nyos jumps from 12 -25 so have to pick one of those two. i doubt it was and was prob closer to 18-22ppm. I trust tonight's reading. now i dosed no NO3 in last 24hrs. I will continue to dos zero NO3. I just don't want to end up with NO3 being the limiting nutrient.

not sure if I should leave PO4 dose where it is or lower it. obv I like to hit that magic # of .01-.02 ppm. I am hoping I hit some level of saturation. but how do I tell?

alk continues .1dkh per day

 

[becon776]

once again I am losing my mind. last night took no3 offline and lowered po4 dos to 14. tonights numbers

po4- 0.00ppm
no3- 5ppm

I dint know what to do??drag out no3 AMD bring back online then increase the PO4 dose? I lowered photoperiod on my small fuge to 2hrs I dint know how short I can make it and still have the chaeto live?
I obviously have not achieved saturation in tank with the zero phosphate levels. so will up that to 20ml. I mean there IS NO WAY my tank is utilizing this much PO4 per day. where is it going???

since there is still NO3 present and I'm tired I am going to hold on the NO3 for now.

I am sending a sample for icp tomorrow we will see.

 

[Randy Holmes-Farley Verified Community Expert]

I'm not sure how your ml dosed numbers convert to ppm dosed, but I'd pick a reasonable dose of nitrate (say, 2 ppm per day) and phosphate (say, 0.02 ppm per day) and stick to it for an extended period while monitoring it every few days. Trying to correct dosing too fast is tricky.

 

[becon776]

tonight tests skipped last night
PO4 - .07ppm hanna Lr
NO3- 5ppm NYPD

lowered po4 dosing down to 14ml of neophos. I will keep NOT dosing NO3... too late to do calculations for ppm. plus had some woodford reserve so...lol.

 

[Randy Holmes-Farley Verified Community Expert]

Those numbers look good.