The Whole Shebang

[Vale!]

I haven't yet done today's tests - I've given up on attracting Pass Ltd's attention for the time being and have ordered a Chinese (I think) copy of the instrument. It's due to arrive any minute, so I'm kind of hanging on ; of course I can always come back and edit the conductivity value later. But that's not why you called ...

I went to look at the length of water that had been drawn up the airline overnight and couldn't see the level. I was nonplussed for a second or three, then I looked at the level in the measuring tube and understood. I followed the airline towards the bucket until I found where the water had got to - it's hard to see on the following pic, so I've added an arrow to help :





It was only a few inches from reaching the bucket itself! I figured if I manipulated the airline so I could apply my ruler it might upset everything, so instead I measured the amount of water that it took to return the measuring tube to brim-full : it was 7mls. That's pretty impressive. I wonder whether the tests might give a clue as to who, or what, might have been responsible? We'll see when my patience with the delivery driver runs out!

[Vale!]

Day 118 (following re-immersion)

Current run began Day 115, 16th March

Temp 25.8C
EC 358*uS/cm [up from 354 yesterday ; up from 112.6 at re-immersion]
pH 4.07* [down from 4.12 yesterday ; down from 6.18 at re-immersion]
TA 1.0926mg/l [down from 1.4568 yesterday ; down from 1.9302 at beginning of current run]
Ni 0.006mg/l [down from 0.032 yesterday ; down from 0.493 at beginning of current run]
Na 129.35mg/l [(x2 dil.) up from 100.11 yesterday ; up from 122.26 at beginning of current run]
O2 X [was 5.9mg/l at beginning of current run]

* New electrode unit fitted to meter. Suspect slightly over-reading. Awaiting confirmation from Pass Ltd. that all is well, or otherwise (they haven't responded to my three most recent enquiries ; the staff member who had been looking after me reliably since last March retired just before Christmas).


The airline has been reset and the measuring tube is brim-full again.

I think I need to do some maths to work out the percentage changes in ammonia, nitrite and nitrate over the last three days (when I've been estimating the volume of water drawn up) and see if anything screams out as Prime Suspect.

No further bucket action today.

[Vale!]

Day 119 (following re-immersion)

Current run began Day 115, 16th March

Temp 26.1C
EC 310*uS/cm [up from 112.6 at re-immersion]
pH 3.98 [down from 4.12 yesterday ; down from 6.18 at re-immersion]
TA 0.8376mg/l [down from 1.0926 yesterday ; down from 1.9302 at beginning of current run]
Ni 0.004mg/l [down from 0.006 yesterday ; down from 0.493 at beginning of current run]
Na 124.92mg/l [(x2 dil.) down from 129.35 yesterday ; up from 122.26 at beginning of current run]
O2 X [was 5.9mg/l at beginning of current run]

* New EC meter now in operation, calibrated OK. It's not Chinese (it's a US manufacturer) but the UK distributor writes advertising blurb and instructions suggesting that it might be! It reads in mS but I'm multiplying to convert that to uS before entering the result here. Approximately 50uS has to be subtracted from each of the previous EC readings to make them more-or-less accurate. I don't know whether or not to go back and do that. Any opinions?

12mls of water was sucked out of the measuring tube overnight! I'd checked it after 9 hours and the water level had risen to just above where the green rigid tube meets the attached airline. So by far the majority of the sucking occurs during the latter 12 hours.

I looked again at the abstract of the paper (that I mentioned in passing upthread) which suggests a chemical decomposition of nitrite at low pH. But the product of that, according to the paper, would be an emission of nitrogen oxides, not a sucking-in of atmosphere (though I suppose both could be happening simultaneously). Anyway, I've attempted to contact one of the paper's authors ; given that it was published 20 years ago it's unlikely that I'll get a response - but you never know!

No further bucket action today.

[Vale!]

Day 120 (following re-immersion)

Current run began Day 115, 16th March

Temp 26.0C
EC 320uS/cm* [up from 112.6 at re-immersion]
pH 3.94 [down from 3.98 yesterday ; down from 6.18 at re-immersion]
TA 0.5705mg/l [down from 0.8376 yesterday ; down from 1.9302 at beginning of current run]
Ni 0.006mg/l [up from 0.004 yesterday ; down from 0.493 at beginning of current run]
Na 149.73mg/l [(x2 dil.)up from 124.92 yesterday ; up from 122.26 at beginning of current run]
O2 X [was 5.9mg/l at beginning of current run]

* I forgot to mention that 10uS is the best resolution I can get from the new EC meter, but that's fine.

After 12 hours water in the airline had barely moved if at all, and not much more at 20 hours. At 23 hours it was obviously moving so I marked the level and left it for two hours after which it had progressed only 3mm towards the bucket! To refill the measuring tube brim-full required 3.6mls of water. I'm thinking that once I establish a pattern I might be able to use hydrogen peroxide to gauge whether it's oxygen that's being thieved from the headspace in the bucket.

No further bucket action today.

[Vale!]

Day 121 (following re-immersion)

Current run began Day 115, 16th March

Temp 26.1C
EC 320uS/cm* [same as yesterday ; up from 112.6 at re-immersion]
pH 3.93 [down from 3.94 yesterday ; down from 6.18 at re-immersion]
TA 0.3399mg/l [down from 0.5705 yesterday ; down from 1.9302 at beginning of current run]
Ni 0.007mg/l [up from 0.006 yesterday ; down from 0.493 at beginning of current run]
Na 124.92mg/l [(x2 dil.) down from 149.73 yesterday ; up from 122.26 at beginning of current run]
O2 X [was 5.9mg/l at beginning of current run]


* My Department Of Administrative Affairs (Purchasing Sub-Committee, Metric Hardware Working Group) reports an egregious error. It seems that having gathered and moved to online basket two potential candidates to replace the iffy Extech instrument, a member of staff authorised purchase before appropriately editing said basket. As a result, the device that I'm currently using for EC measurements is not the one I was expecting! The real one has not yet been delivered. The member of staff involved has been summoned to a disciplinary hearing before the Incompetent Seniors Board and, irrespective of its result, the few pounds in question already has been docked from his salary.

Not much bucket-sucking overnight : it took 2.8mls of water to restore the measuring tube to brim-full.

No further bucket action today.

[Vale!]

Day 122 (following re-immersion)

Current run began Day 115, 16th March

Temp 26.2C
EC 320uS/cm [same as yesterday ; up from 112.6 at re-immersion]
pH 3.92 [down from 3.93 yesterday ; down from 6.18 at re-immersion]
TA 0.2306mg/l [down from 0.3399 yesterday ; down from 1.9302 at beginning of current run]
Ni 0.009mg/l [up from 0.007 yesterday ; down from 0.493 at beginning of current run]
Na 128.47mg/l [(x2 dil.) up from 124.92 yesterday ; up from 122.26 at beginning of current run]
O2 X [was 5.9mg/l at beginning of current run]


It took 4.1mls of water to refill the measuring tube, yet the level of water in the airline hadn't progressed towards the bucket much more than it had done yesterday (when it needed 2.8mls to refill). That's odd.

Also I forgot to mention that I did another phosphate test on Day 121 : it was at 0.37mg/l. So it had risen to that from 0.17mg/l on Day 116. That may well indicate that some microblighters have discharged their contents.

No further bucket action today (actually yesterday, because I'm entering this a day late!).

[Vale!]

I haven't done today's tests yet owing to being dumbfounded! The 'oddness' that I remarked upon yesterday got odder overnight :




The water in the airline had advanced a few centimetres towards the bucket (as per the last couple of days) but no less than 11.4mls of water was required to refill the measuring tube! I don't understand. So far as I can tell from a glance the airline beyond the meniscus pictured above is quite dry so it doesn't look as though it advanced and then fell back (the measuring tube would surely have refilled anyway if that were the case).

I'd better check the airline for dryness much more carefully when I go back downstairs - one explanation could be that the water did actually reach the bucket. If so it would have supplied some dissolved oxygen. Microblighters may have used that to do some processing (of ammonia and/or nitrate) and, in doing so, caused gas to be produced which pushed the meniscus back down the airline towards the measuring tube.

I can see myself setting alarm clocks so that I can check what's happening regularly throughout the night. It'd be like having a baby in the house again!

[plankton]

Will there be much evaporation where it is, or could it get knocked?

[Vale!]

It's an unheated room, P, so evaporation should be negligible in context?

I had already considered Rufus, our cat, but he would most certainly have knocked over the measuring tube if he'd tried to extract that much water from it! He knows full well that any interference in my fish area results in a 'lives-minus-one' situation, so steers clear (unless he wants to exit via the patio doors).

Thank you for thinking about this.

[Vale!]

Day 123 (following re-immersion)

Current run began Day 115, 16th March

Temp 26.1C
EC 320uS/cm [same as yesterday ; up from 112.6 at re-immersion]
pH 3.93 [up from 3.92 yesterday ; down from 6.18 at re-immersion]
TA 0.7284mg/l [up from 0.2306 yesterday ; down from 1.9302 at beginning of current run]
Ni 0.007mg/l [down from 0.009 yesterday ; down from 0.493 at beginning of current run]
Na 124.04mg/l [(x2 dil.) down from 128.47 yesterday ; up from 122.26 at beginning of current run]
O2 X [was 5.9mg/l at beginning of current run]

Ammonia surge! I told myself to do phosphate when I saw that - but of course immediately forgot to do so.

Yes - the airline was dry on closer inspection, with no evidence of water having passed through it.

No further bucket action today (apart from monitoring the airline as best as I can).