Starting A Fishless Cycle

[OldMan47]

RO water is water that has been passed through a semipermeable membrane. That membrane is tight enough that the water molecules have a hard time moving through it and most of the minerals that are in water have an even larger molecular size. What ends up happening is only the water gets through and the minerals are left behind. Since the minerals would quickly plug the membrane, the side the water comes from is being continuously flushed to prevent any kind of build up. The flush water becomes waste and is put down the drain while the water going through the membrane is stored or used immediately, depending on the setup. In my kitchen, the clean water goes to a small storage tank under the kitchen counter and the waste water goes right into the drain from the kitchen sink. The amount of water wasted to keep the RO functioning properly varies from about 4 times the water produced, in a modern RO, to about 10 times the water produced, like in my antique RO unit. Much of the purified water sold for drinking in the US and other parts of north america is produced using RO systems with high pressure pumping systems to produce water faster than an RO in a home could ever do.

 

[danb]

i prefer your answer to mine

Any help with the nitrite guys? Yesterday was turning grey after a couple of minutes, today it goes from purple to pale blue (0ppm) in 2 minutes. Does this mean the nitrite part of the cycle is done now and i should be reading it at 0ppm?

 

[waterdrop]

Hi danb,

Looking at your log, you appear to be transitioning from the second phase to the third phase of fishless cycling. During this transition its common for the nitrite to "bounce around" and be kind of unpredictable from one test to the next. Eventually it should settle down and always be dropping to zero within 24 hours. The third phase is all about waiting for the nitrite drop to get faster, ie. instead of dropping to zero in 24 hours is drops to zero in 18 hours, then 12 hours (where our qualifying week compromise happens) or even 10 hours or 8 hours. Sometimes in the third phase while you're focused on nitrite getting faster, the ammonia will "stumble" and show some trouble clearing in 12 hours, even if it was doing it reliably earlier on. All of this will eventually go away with enough patience and a true biofilter will emerge, one that will -always- clear all traces of ammonia or nitrite within 12 hours or less.

~~waterdrop~~

 

[danb]

Thats great thanks. I mean its not fluctuating daily just when im testing at the bottom of the tube it turns purple, then i shake it and it gets lighter and lighter till after 2 minutes its blue. Was wondering if this means the nitrite is 0?

 

[fatheadminnow]

Thats great thanks. I mean its not fluctuating daily just when im testing at the bottom of the tube it turns purple, then i shake it and it gets lighter and lighter till after 2 minutes its blue. Was wondering if this means the nitrite is 0?

Your nitrite drops turn to purple right when they hit the water in the test tube/when they reach the bottom? This means that your nitrite is off the charts. There has been numerous discussion on this topic in the past.

-FHM

 

[danb]

Thats great thanks. I mean its not fluctuating daily just when im testing at the bottom of the tube it turns purple, then i shake it and it gets lighter and lighter till after 2 minutes its blue. Was wondering if this means the nitrite is 0?

Your nitrite drops turn to purple right when they hit the water in the test tube/when they reach the bottom? This means that your nitrite is off the charts. There has been numerous discussion on this topic in the past.

-FHM

Yeah i've read that before but everyone said that it then turns green, however its turning the same pale blue colour as 0ppm so just wasnt sure.

 

[danb]

for the last 4 days the ammonia has been eaten up in under 24 hours. Do you think i should start to see some movement with the nitrite soon?

 

[OldMan47]

When the ammonia is regularly processing in under 24 hours, it is time to back off a bit and only dose up to around 2 ppm of ammonia. That way the nitrite levels will only reach maybe a hundred ppm before nitrites start processing well. It often takes about 3 weeks after the ammonia is processing well before you will see the result on your nitrite tests. What happens goes something like this. You get about 2.5 ppm of nitrite for each 1 ppm of ammonia that is converted. Let's say it takes a week at 2 ppm before the nitrites start to process enough just to keep up with the 5 ppm each day of nitrites being added. By then you have 7 x 5 ppm or about 35 ppm of nitrites. If a few days later you are moving 8 ppm of nitrites, you will have a daily net gain of 3 ppm. How long will it take before you can measure the 3 ppm daily drop? The test only goes up to 5 ppm so it will take several days, maybe a whole week for that level to be reached. The next day you are at 1 or 2 ppm and the next day at zero. What it looks like, when you can't tell what was happening is simple. You have recorded well over 2 weeks of off-scale readings and didn't know that anything was happening at all. Suddenly the nitrites are being processed and it is a surprise. If you start by using 5 ppm additions instead of 2 ppm, your nitrites are going up by 12.5 ppm daily and you reach 90 ppm in that same week before things change direction. It is worse than that because when you reach the point of processing that 8 ppm daily, you are still losing ground and the levels are still climbing. A few days later, of course, you reach a point where you can move the 12.5 ppm of nitrites daily and the same scenario happens where after a while the levels suddenly appear in your test results at a value you can read. Once again the next day it looks like the nitrites started processing out of nowhere and are now completely under control.
You are now in the nitrite spike of a cycle and should back off the additions until your readings can be observed again. At that point we challenge the nitrite processors by bumping the ammonia levels back up to 5 ppm daily. It should take almost no time for your nitrite bacteria to be able to catch up with a good head start at 2 ppm of ammonia daily.

 

[danb]

Thank you very much for that. I will start dosing just 4mls when it reaches 0 now and when i see the nitrite drop ill bump it backup to 9mls - 5ppm.

It seems to take forever

 

[waterdrop]

It seemed to take forever to me too but now that the fishless cycled tank has had fish for more than 2 years, I find on looking back that the fishless cycling time now seems to have been very short by comparison and I'm thankful for every bit of knowledge I gained during that time.

~~waterdrop~~

 

[danb]

Hopefully i will be saying the same as your saying in 2 years time WD

My cycle doesnt seem to be doing anything just now. Been stuck with more or less the same nitrite and nitrate for couple of weeks. I just need to keep at it and wait for the nitrite to drop?

I seem to be adding ammonia everyday for the last week or so, so something must be happening!

 

[waterdrop]

I am worried that your nitrate(NO3) test is not coming out accurately and that actually you may have high nitrates in the tank and are inhibiting the growth of the N-Bac population. Have you ever done a 90% water change with recharge of ammonia and bicarb? I think I would do this, at a convenient time, and maybe even increase the bicarb some to see if you can get the recharged pH to go higher than 7.6 for a while.

What types of media are in the filter?

~~waterdrop~~

 

[danb]

It is the standard media that comes with the tetratec ex1200 - the carbon. So its a few sponges, ceramic noodles, some plastic ball things and a couple of extra sponges to put in my other new filters for the other tank.

The nitrate has always been at a steady 5-10 from about 2 weeks in iirc. With the occassional jump to 80 which could has been a incorrect result.

Also i havent changed any water, just kept topping it up every now and then. I didnt think i would need to do the 90% till the end of the cycle?

 

[waterdrop]

Well, if a Fishless Cycle proceeds ideally, we like to not disturb it with water changes. Water changes can be a bit of a jolt to the process and it sometimes takes a day or two for the readings to make sense again afterward. But in your case the cycle is not proceeding ideally and so we need to think about trying some things in my opinion.

The water in the tank during a fishless cycle is really just our "bacterial growing soup" and we are guessing at how to make it ideal for the bacteria. We already know of course that the ideal temperature is warm, 84F/29C being my favorite flavor of warm, and we know from Hovanecs studies that a pH of 8.0 to 8.4 is ideal for our two species (Nitrosomonas spp. and Nitrospira spp.) and we know that the process slows as the pH drops below that, stalling at pH=6.2 and stopping at pH=6.0, assuming the pH drop has been fairly quick. The part we don't know are the hundreds of other inorganic and organic substances that are in the water and that we can't afford or don't have time to test for, so there are plenty of unknowns. One small thing we know is that the bacteria need some calcium and iron, which generally come in with fresh tap water. We also know they don't grow well once the concentrations of nitrite(NO2) and nitrate(NO3) get too high (which of course is frustrating because those are of course the intermediate and final products of the very cycling we are doing!) We also assume there might be some trace heavy metals that we don't want to see in too high a concentration.

All of this means that although we don't like disturbing things with water changes, we can sometimes actually change things by -doing- a big water change or two during the course of a fishless cycle if it gets slow. In your case things are now so slow that I think this work could not hurt and may very well help things. Particularly if you've had a dry winter and have been topping up, you will have added to the excess heavy metals. But really, the most compelling reason is to try and really clear as much nitrite and nitrate out of there as possible and let those things start building up again. Your sand is just playsand or from an aquarium shop? I'm assuming there are no questions about it.

~~waterdrop~~

 

[danb]

thank you for taking the time to reply.I wasnt wanting the answer you gave as i have a bad back annd struggled to change the water for the tank with fish in yesterday but oh well! its my own fault

Its just regular play sand from argos which the majority of the people from the uk tend to use.

How much water should i change? Im thinking ill just syphon it out of the window.