What is the possible reason of such spike in a 11month mature tank??? Any idea bro?
Is your display tank containing dsb?
When 30'/. wc/ week can't decrease the conc. of NO3 .....there must be something wrong.
O.K. I can suggest you, what I have done and got a good result.
Its well known ''vodka method''.
Though sugar or viniger methods are also well known, but these methods are quite controversial and there is no perfect direction of use and proper results of them.
Where as ''vodka method'' is quite discussed and I got many good remarks 'bout it from various communities worldwide.
Now the process ......what I've applied too.
1st calculate your entire water volume......water volume of DT+sump+skimmer. Also calculate how much tank area has been occupied by your lrs. If its seems tough, then minus 30'/. water volume from gross and u can get an approx net volume.
BTW, good protein skimmer is the key in this process.......except it you never get an ideal result.
Now first measure your tank NO3 level wth good kit. Then for 1st 3days add 0.1ml vodka for per 25G or 100lit net water volume. That means if your system contains 200lit water, then you have to charge 0.2ml vodka per day.
Then for next 4days, add 0.2ml of vodka for per 25G or 100lit of water.
After 7days, re-measure NO3 level. If its start dropping then carry forward the running vodka volume per day untill NO3 seems undetectable. If its not working after ending of 1st week then just double the volume of vodka per day for next 7 days and re-check then. Also add additional 0.5ml vodka after each subsequent week without any doubt. That means in the 2nd week your dose 'll be 0.7ml per 25G.
You can get a heavy skimming in this period, its normal.
Also, few says they got a little cloudy water in first phase. But if its too cloudy, that means it a huge colony growth of denitrifying bacteria, and you must stop dosing. Water 'll be clear within next 24-48hrs.
Its just my suggestion as I've got good results in case of NO3 & PO4 conc. reducing.
But, each tank is differant and water chemistry is differant. So, b'fore start it read more bout vodka method. Never use vodka with any flavour. Most cheap vodka can do it very well.
Now ball is in your court.
Best of luck........
THERE IS NOTHING AS TRANSPARENT AS WATER. BE TRANSPARENT, AND WORLD COMES TO YOU THE SAME. ALWAYS KEEP SMILING.....