The DoS and Resovoir are on sale as a package deal for around $450 which is an okay deal. Back when I was shopping The DOS was $349 and the Resovoir was 199 so it was $100 more and that is when they were getting a lot of complaints.
Were I shopping now I would probably jump on the combo deal but......I got two of the BRS dosers and as it turns out, if you have outlets 4 and 8 free on your apex you are just as well off with BRS. Just run each pump for 10 minutes and write with a piece of what tape on each pump the true flow rate (one of mine is 2.05ml/min and the other is 2.15. From there, if you can do math you can easily figure out how long to run the pumps and what part of the day.
I should point out that I am a registered nurse and used to mix emergency drugs for patients during codes and calculate drip rates pretty much in my head in things like ml/kilogram/min so what I find relatively trivial to do as far as the calculatios, I could forsee some having serious problems doing...... your mileadge may vary but for me they turned out to be so easy to program that I doubt ill ever use the DOS now. Ill probably use my extra 1-link connection for a COR (and hopefully a flow sensor) when apex releases those instead.
I set out to buy every single piece of equipment apex offers but it turns out a few things you just really don't need. A DOS, a salinity monitor/probe, and a dissolved oxygen sensor. Some will argue you don't need ORP but I actually find a lot of benefit to having continuous read out of basically what amounts to how much organics are in my water. I find the break out box and float switches indespinsible and I am looking forward to the fluid monitoring system coming out. The leak detectors and an extra EB8 also are things I couldn't do without....along with the pump and light modules for my hydras and vortechs. I don't have the PAR kit and I honestly just can't make up my mind on that one... Lighting is tricky..and I think the PAR kit might have some value even at the high cost.
Will I upgrade to a DOS one day? Possibly. They are extremely feature rich. Were I not so good at calculating drip rates I could see rationalizing the cost. One feature that kind of like is the resovoir gives you the fluid levels but unless you are dosing A LOT I find that I'm usually very well aware of when my levels are low and need filling.
What I would really like to see is something like a syneye that could give you real time measurements of calcium, alk, mg and possibly nitrates and phosphate levels via probes I would proably cought up big money to automate that.
