Statistics: Posted by Dixiedean — Mon Apr 27, 2020 10:38 pm

]]>

We just added a pond volume calculator to our website. Just input the dimensions of your square, rectangular, or round pond and it will quickly display gallons or litres. No maths, no guesswork!

Pond Volume Calculators - Kitsu Koi

Statistics: Posted by Kitsu koi — Thu Apr 16, 2020 1:00 am

]]>

]]>

Statistics: Posted by Sopersonic74 — Wed Aug 22, 2018 7:32 am

]]>

http://www.vinidex.com.au/technote-parent-page/dos-and-donts-of-solvent-cementing-pressure-pipes/

Statistics: Posted by Dixiedean — Tue Aug 21, 2018 9:02 am

]]>

]]>

First off the example doesn’t work. If the passengers can’t remove it quickly enough at double the speed and only 50% manage to do so, then chances are only 50% will manage to do so on the second pass because of the speed, and so on. The faster it goes, the less likely people are to be able to grab their luggage.............An analogy that doesn’t illustrate the point at all, therefore renders the whole thing to be incorrect.

The analogy works for me providing everything else stays constant.

Say it's the world's slowest airport carousel and biggest plane load of folks are waiting - after 1 hr the carousel has gone round once and everyone has collected their bags (ie ammonia = 0 after 1hr).

The airport manager thinks he can speed the process up and doubles the carousels speed compared to the first plane. The second plane lands with the same number of passengers but after one revolution only 50% of the bags have been collected but now there's more room everyone who's still waiting to get their stuff can get to the front and grab their bag as it comes round on the second pass. The net result is exactly the same, ie after one hour everyone has collected their luggage - and the ammonia reading is 0 again.

Now what Manky is saying is that actually you're right, the analogy will never be quite correct because there are always passengers arriving on smaller planes (ie your fish are still creating ammonia during that hour) but the example works at a basic level and for me that's exactly how I need it explaining.

You might disagree and that's fair enough - I'd be interested to know what your theory is on it though. Cheers, M

Statistics: Posted by Airlite — Sun Jun 03, 2018 11:12 pm

]]>

]]>

If a luggage carousel at an airport rotates slowly enough to deliver luggage at the same rate as passengers can remove it then the carousel will be emptied as it completes each revolution. If the speed is doubled so that the passengers can’t remove it quickly enough then 50% of the luggage will go round a second time. After the second revolution the remaining 50% of the luggage will have been removed and the total time taken to remove 100% of the luggage will have been exactly the same as in the slower speed example.

First off the example doesn’t work. If the passengers can’t remove it quickly enough at double the speed and only 50% manage to do so, then chances are only 50% will manage to do so on the second pass because of the speed, and so on. The faster it goes, the less likely people are to be able to grab their luggage.

Given that this is the logic being used here, then it follows through to the ammonia removal in the filter surely.

It’s an analogy

Statistics: Posted by Sopersonic74 — Sun Jun 03, 2018 3:09 pm

]]>

If a luggage carousel at an airport rotates slowly enough to deliver luggage at the same rate as passengers can remove it then the carousel will be emptied as it completes each revolution. If the speed is doubled so that the passengers can’t remove it quickly enough then 50% of the luggage will go round a second time. After the second revolution the remaining 50% of the luggage will have been removed and the total time taken to remove 100% of the luggage will have been exactly the same as in the slower speed example.

First off the example doesn’t work. If the passengers can’t remove it quickly enough at double the speed and only 50% manage to do so, then chances are only 50% will manage to do so on the second pass because of the speed, and so on. The faster it goes, the less likely people are to be able to grab their luggage.

Given that this is the logic being used here, then it follows through to the ammonia removal in the filter surely.

Statistics: Posted by GSARider — Sun Jun 03, 2018 1:55 pm

]]>

Dwell times aren't as important as some people used to think. Bakki Showers and Nexus filters get good reports but the dwell time for any particular drop of water can be measured in seconds. The reason why dwell times aren’t important involves understanding the advanced mathematical concept of differential equations that many of us will have covered in maths lessons at school but few would want to remember.

The simplified way to look at what is happening when a continuous supply ammonia (and nitrite) is “fed” to a biofilter is like this:

If a luggage carousel at an airport rotates slowly enough to deliver luggage at the same rate as passengers can remove it then the carousel will be emptied as it completes each revolution. If the speed is doubled so that the passengers can’t remove it quickly enough then 50% of the luggage will go round a second time. After the second revolution the remaining 50% of the luggage will have been removed and the total time taken to remove 100% of the luggage will have been exactly the same as in the slower speed example.

Presenting ammonia (and nitrite) to a biological media isn’t quite the same as that simplified example because a pond is a dynamic system where ammonia is being added all the time by the fish in it but, in essence the same principle applies. If the turnover rate is slow then 100% of the ammonia will be removed on the first pass or, if the turnover rate is twice as fast, the bugs will only have time to remove 50% and will take two passes to remove it all.

Will the background level of ammonia in the pond be different with either method?

This is where a mathematical model becomes hard to understand but there will be no difference. Simplifying again:- Take two typical turnover rates, once per hour or twice per hour. With the 30 minute rate, let’s assume that 50% of the ammonia will go back to the pond. This may seem to be a bad thing but the fish will only have 30 minutes to add more ammonia. If the turnover rate was once per hour then 100% of the ammonia will be removed by the bugs so 0% ammonia will go back to the pond BUT the fish will have had 60 minutes to make more so the background level in the pond will be the same in either case.

Can the turnover rate be too fast for the bugs?

Provided the flow isn’t so fast that the bugs aren’t jet washed away the answer is “no”. Bugs don’t sit on a surface waving little hands in the water trying to catch molecules of ammonia (or nitrite) as they whistle past. They live in biofilms where water slowly percolates through the matrix regardless of the water speed over the surface.

I haven’t covered dwell times on my website (note to self – good idea) but I drew a diagram for a series of articles I was commissioned to write and one of the diagrams in part 1 shows what a biofilm looks like. That may be helpful to anyone who wants to understand how water containing ammonia (and nitrate) percolate through the matrix.

http://www.mankysanke.co.uk/html/good_w ... _pt_1.html

Statistics: Posted by Sopersonic74 — Sun Jun 03, 2018 8:24 am

]]>

I usually make mine a fraction stronger, which is the 130grams to 1 litre

I make a stock solution of 65grams to 500ml and the most important thing I do is keep it in a previously used dechlorinator bottle. That way no mistakes of using the wrong clear chemical

Statistics: Posted by Sopersonic74 — Tue Oct 04, 2016 5:07 pm

]]>

Statistics: Posted by Pondwithnoname — Mon Oct 03, 2016 9:19 pm

]]>

]]>

]]>