# Bi-weekly water changes and EI



## killi69 (7 Jun 2012)

Hi there,

In the algae thread, I received some useful advice to do 50% water changes twice a week until the algae problems have disappeared in my new tank.
http://www.ukaps.org/forum/viewtopic.php?f=19&t=21848

I would like to know whether I need to adjust the EI dosing regime if I am doing water changes twice a week, instead of once a week??

Thanks for your help.

Regards
Andre


----------



## ceg4048 (7 Jun 2012)

Hi,
 The answer is listed in the EI tutorial thread itself (at the bottom of page 17)
http://ukaps.org/forum/viewtopic.php?f= ... &start=160 or on other dedicated threads such as http://ukaps.org/forum/viewtopic.php?f=11&t=13285

Cheers,


----------



## Iain Sutherland (7 Jun 2012)

Hey clive, havent seen you on for a while... first off my tank is looking way better since heeding your advise again so thanks  

EDIT*
On the topic of twice weekly WC... i have always split the 2  'rest' days as WC days and fitted the usual dosing schedule around those.  Would this solution be less preferable to the linked way?? If EI always runs in excess anyway would the addition export from WC really need the additional dosing to compensate?  
Assuming that most dont run running silly lighting to even come close to the EI nutrient usage?


----------



## ceg4048 (8 Jun 2012)

Hiya mate,
                 It's good news that things are looking better in the tank.

Whatever way that works for you is the one that's preferable. EI is not married to any particular set of techniques or schemes. At the end of the day, as long as the plants are not suffering deficiency then your way of doing it is sound. I just have a particular way of thinking and I always try to be systematic in my approach so that I make fewer mistakes if the situation changes because I depend on a system that is robust enough to take into account as many variables as possible. A lot of different things can happen, like a trip out of town, or an extra water change due to some other factor. You would be amazed at how quickly a tank with extreme levels of biomass can deplete the nutrient levels, especially when NOT using an enriched substrate.

Since I always change my water on a Sunday I then mentally associate every water change with a Sunday, so that a midweek water change then makes me think in terms of a Sunday water change. So I can never get confused if I think about it this way even doing 2 or 3 water changes per week, since my personal system of dosing intervals is referenced to the Sunday water change.

Your method is based on an assumption which may be valid for now but may not be as valid if some conditions in the tank, or if situations in your daily schedule varies. But for now, if it works for you then it's just as good as any other. 8) 

Cheers,


----------



## killi69 (8 Jun 2012)

Ceg and Iain, thank you both for your advice.  Much appreciated


----------

